Tuesday, December 24, 2013

Strength Training: Practical Application, Sample Workouts

First, let's review some key components of strength training.

In my last post, I summarized the findings of a recent review from Ronnestad and Mujika. The take-home message: strength training is generally beneficial for runners and cyclists and "...there are no reports of negative impacts of concurrent training on endurance performance" ( Ronnestad & Mujika, 2013).

There are many ways to approach strength training. By varying exercise, load, volume and recovery time the athlete can change the focus of the workout. In the table below, I've tried to summarize what we know about volume and load manipulation for different adaptations.

Focus
Volume
Load
Recovery
Strength (Neural)
Low (1-6 reps)
High (≥80% 1RM)
Long (5+ minutes)
Power
Low (3-6 reps)
Varied (30-90% 1RM)
Long (5+ minutes)
Hypertrophy
Moderate (8-12 reps)
Moderate (60-80% 1RM)
Short (1-2 minutes)
Muscular Endurance
High (12+ reps)
Low (30-50% 1 RM)
Short (1 minute)

I would like to point out that lifting heavy loads with low volume is generally done with the intent of increasing maximal strength, but as maximal strength increases, so can endurance at a given submaximal load. Some believe that there is only one way to improve muscular endurance - through high repetitions and lighter loads, but this simply isn't true.

Here's an example, using fictional athletes:

Jim has a back squat 1RM of 100kg, while Sam has a 1RM of 85 kg. Now, who can complete the most reps at 80 kg? For Jim, 80kg is 80% of his 1RM, but for Sam, 80 kg is 94% of his 1RM. Jim will likely be able to rep the load 7-8 times, while Sam may only be able to get 2-3 reps (Estimating 1RM). So we can agree, Jim is stronger and more fatigue resistant at a given submaximal load (<85kg).

Another way to look at it would be to compare total work done in a set number of reps at a given percent of 1RM. If Jim lifts 3 reps @ 90% 1RM, he completes more work than if Sam lifts 3 reps at 90% of his 1 RM. More work in the same amount of time... that's like running or riding further in a given amount of time.

This is not to bash high rep, low load training. Certainly, one can gain muscular endurance from that. But if an athlete only focuses on those sorts of exercises (like bodyweight squats or lunges), he may eventually be limited by his maximal strength. If Sam does hundreds of bodyweight squats a week for months, he will never be able to complete 10 reps at 100% of his 1RM (85kg), or be able to lift Jim's 1RM of 100kg. All he needs to do is improve his maximal strength, and to do this he has to apply the right stimulus of heavy loads (Brown, 2007).

Below I've outlined a basic routine for a distance runner and a cyclist. Yes, the programs may change depending on the athlete's experience, goals, injury history, and so on, but I want to provide a basic framework for an example. The primary goal here is to increase maximal strength through neural adaptation. These routines would be best done when overall running or cycling volume and intensity is low - perhaps pre-season or "off season," and done 2-4x per week. You can click on the exercise for a link to a demonstration.

Distance Runner
Back Squat
Deadlift
Step-ups OR Forward/Backward Lunges
Calf Raises OR Calf Press
Hip Thrust
Military Press
Pull-ups

Cyclist
Back Squat
Deadlift
Leg Press
Hip Thrust
Hamstring Curl

It's that easy. Remember, we want to maximize strength and minimize hypertrophy (endurance exercise may also help limit hypertrophy), so all of these exercises would be done with high loads, low volume and long recoveries between sets. Perhaps 80-90% 1 RM with 3-6 sets of 3-6 reps. For secondary lifts, like lunges, step-ups, leg press, etc.,  I don't set 1RMs. Instead, chose a load that is difficult to complete for 6-8 reps.

These workouts could be repeated 2-4x a week or the athlete could use different variations of the lifts. For example, back squat could become front squat or box squat for the cyclist. Deadlift could become stiff-legged or single-legged. But I think the above exercises will enable the athlete to place the most load on the system; I cannot front squat as much as I can back squat, so which gives me the best stimulus for strength gains?

Now maximal strength is certainly not the only piece of the equation. Once you've developed strength, then you can shift your focus to power with jump squats, power cleans, hill sprints, etc. In addition to these strength routines, I would also suggest completing a few core specific movements - especially for the runner or multisport athlete. It's easy to tack those exercises on immediately after the main session. But that's a topic for another day.

Brown, L. E., & National Strength & Conditioning Association (U.S.). (2007). Strength training. Champaign, IL: Human Kinetics.


Ronnestad, B. R., & Mujika, I. (2013). Optimizing strength training for running and cycling endurance performance: A review. Scand J Med Sci Sports.

Monday, September 23, 2013

Strength Training for Distance Runners and Cyclists: A Look at a New Review

A recent review from Ronnestad and Mujika has evaluated the effects of strength training programs on performance and the components of performance in runners and cyclists.

An abstract can be found here.

As I found with my literature review for hill sprint training (here and here) this review notes that strength training, either heavy-weight and slow or light-weight and explosive, improves running economy. Interestingly, this review states that it may also improve cycling economy, especially as an athlete becomes fatigued.

Ronnestad and Mujika also evaluated the effects of strength training on VO2max, lactate threshold/anaerobic capacity, and performance measures.

I have written on concurrent strength and endurance training in the past, questioning what effect(s) endurance training might have on strength for the strength and power athlete. While this review is concerned with concurrent training, it is strength training for the endurance athlete - and it appears that there is no detriment to endurance performance when strength training is done properly in conjunction with endurance training. I am not sure the opposite is true; based on the evidence we have now, I certainly still believe endurance training may inhibit strength gains for the pure strength and power athlete. Still, I do not believe the most effective timing of concurrent training has been established (same day vs. alternate day, same session vs. separate sessions, etc.).

To help summarize the findings of the review, here are some excerpts:

"... there are no reports of a negative effect of heavy strength and explosive strength training on either cycling or running economy."

"... running economy can be improved by 2–3 strength training sessions per week, it seems a threshold of (explosive) strength training volume and frequency has to be overcome to achieve improved running economy."

" ...none of the studies on long-distance runners and cyclists report a negative effect of strength training on velocity or power output at the lactate threshold."

"... anaerobic running power can increase substantially after a period of added explosive strength training."

"... there are no reports of negative impacts of concurrent training on endurance performance."

"Strength training contributes to enhance endurance performance by improving the economy of movement, delaying fatigue, improving anaerobic capacity, and enhancing maximal speed."

The most interesting section of the review to me was "Potential Mechanisms." Here, the authors give the following mechanisms as an element for improved performance. They were:

1. Altering muscle fiber recruitment pattern  - postponing fatigue in type I fibers, placing less reliance on the less efficient type II fibers,  improving economy, putting less reliance on limited muscle glycogen, improving sprint performance following endurance activity

2. Conversion of type IIx to type IIa - by recruiting the fastest twitching fibers again and again, they could become more oxidative and fatigue resistant

3. Increasing maximal force/rate of force development - increasing muscle-tendon stiffness, improving running economy, lowering relative exercise intensity - reducing the amount of muscle mass activated to generate submaximal power.

The authors go on to provide "potential negative outcomes." The primary negative outcome is hypertrophy - which would mean weight gain. There is a reason why the best middle and long distance runners are not 100 kg. Hypertrophy could also decrease capillary to muscle area ratio - potentially limiting O2 delivery to the muscle. Despite these recognized potential negative consequences, the authors note that when strength training is done in conjunction with large volumes of endurance training, hypertrophy is inhibited (remember this?).

Overall, this study is another piece of evidence to indicate that strength training for the endurance athlete is an effective mode of improving endurance performance. Table 1, adapted from Ronnestad & Mujika, summarizes the effects of strength training on endurance performance:


Table 1.
Benefits
Possible Negative Outcomes
Improved Economy
Increased Body Mass – Lacking evidence
Anaerobic Capacity
Decreased VO2max – No evidence
Lactate Threshold
Increased diffusion distance – No evidence
Delayed Fatigue
Reduced capillarization – No evidence
Maximal Strength
Reduced Oxidative enzyme activity – No evidence
RFD

Maximal velocity

Endurance Performance



 In my next post, I'll provide sample programs for the distance runner, the cyclist and the multisport athlete.


Ronnestad, B. R., & Mujika, I. (2013). Optimizing strength training for running and cycling endurance performance: A review. Scand J Med Sci Sports.

Sunday, September 15, 2013

Tips from the Top - Where'd you hear that?

I recently defended the student of sport science on a message board. It wasn't pretty.

Vern Gambetta nailed it here, in a much more peaceful way. "All that being said remember the immortal words of Gertrude Stein 'the answer is there [is] no answer.'"

Much like my mentor's saying, "the answer in exercise physiology will always be 'it depends.'"

Where do you get your information from?

Friday, September 13, 2013

Marathon Periodization and Taper

I came across this case study of 3 professional distance runners (Reid Coolsaet, Rob Watson, and Dylan Wykes), following them through a 16 week build towards a marathon, where they would run personal bests of 2:11:23, 2:12:39, and 2:16:17. There is some discussion of their training on pg. 396.

"The 3-week premarathon taper featured a 52% reduction in volume with no appreciable change in training frequency. This taper is congruent with the recommendations from a recent meta-analysis on the effects of tapering on performance, which found the ideal length of taper to be ~2–3 weeks, where training volume was decreased 41–60%, without any modification of training intensity or frequency (BosquetMontpetitArvisais, & Mujika, 2007)."


These guys went from running 142, 165, and 124 miles/wk to an average of 71 miles/wk in the last week including the race. Talk about a taper. If you're running 70/wk that would mean dropping down to ~35 miles (including race distance)... So, this data might not be particularly relevant to the sub-elite crowd, or those running significantly fewer miles - most of us here. And while these athletes have posted impressive times, this is only a case study from 2 training groups; coaches Dave Scott-Thomas and Richard Lee.

Regardless, I think another other interesting bit is that training impulse, a combination of physiological intensity, perceived exertion, and volume, peaked 7 weeks out from the race week. Unfortunately, we don't get the to see much into the specifics of their training.

The article also provides some interesting information on the manipulation of dietary carbohydrate and glycogen status in the athletes (though, muscle glycogen content was never directly assessed). This will be a focus for another day.

Monday, September 9, 2013

"Burnt Cookies" - Overtraining from the Perspective and Experiences of an Exercise Physiologist

I stumbled upon a good read today. The excerpt from Overtraining Athletes: Personal Journeys in Sport, can be found at this link.

The interview with Dr. David Martin, a physiologist with the Australian Institute of Sport, highlights the importance of monitoring athletes' physiological and psychological well being, as well as the value of interpersonal coach-athlete relationships. All around, a good read and sound advice from an experienced professional.

Tuesday, August 20, 2013

Current Research: Pacing Strategies for Multisport

A constant workrate in the cycling portion enabled athletes to cover the 9.3km run 42s faster on average than a variable workrate. Abstract here.

"Training to lower physiological and perceptual responses during cycling should limit the negative effects on triathlon running."

Sunday, July 28, 2013

USATF Level 2

I'm looking forward to the USATF Level 2 Youth Specialization Clinic this week! To all my coaches as a youth -- thank you for sharing the wonderful world of athletics with me.

Wednesday, July 24, 2013

Supplements -- You Should Know

You've probably seen the ridiculous claims on supplements packaging before. Stuff like, "Improves Endurance 45%" or "Accelerates Recovery!"

I've been training and racing for the better part of 12 years. I've seen a lot of garbage, even used it myself when I was younger. But now, I take a multivitamin and an iron supplement -- that's it. Of course, I might consume carbohydrate before, during, and after exercise. And I occasionally use whey protein with a carbohydrate source for a quick and easy recovery shake. I also enjoy a good cup of coffee.

But while supplement companies keep trying to pump you full of their dishonesty and products, I urge you to take the time to evaluate their claims and the research as a whole. The first source I use when I consider a supplement is the Australian Institute of Sport's website. Here you can find their fact sheets on popular supplements as well as their classifications. You'll notice all the Group A supplements are the no-nonsense, heavy hitters -- carbohydrate, whey, caffeine, creatine (in specific circumstances), electrolytes, iron, multi-vitamins, and so on.

There is no (safe or legal) magic pill that will boost your VO2max or improve lactate clearance. Be wary of claims like these.

Friday, July 19, 2013

Concurrent Training - Effects on Strength and Power

I got an email last week with a link to this article from the NSCA's Journal of Strength and Conditioning Research. It caught my attention because I've done "concurrent training" in the past and I'm currently tinkering in the weight room 2-3x a week while running and cycling. Further, it seems as though resistance training for runners is a hot topic as of late.

In my post from March on concurrent training, I essentially concluded that through a number of possible mechanisms, same session strength and endurance training may limit the adaptations that you would get from resistance training alone or in a separate session. For example, if you go for a 2 hour long run then completing plyometrics or a weight workout -- you may not get the benefits from that second workout to the same extent as you would if you had separated those workouts. Cellular signaling, fatigue/overtraining, decreased glycogen content may all be part of the reason. Think about it -- how many sets and reps can you squat at 70% 1RM? Now how many can you squat after a hard set of intervals, or a 2 hour long run at marathon pace? Then go do leg press, lunges, step-ups, etc. My point being -- endurance training may limit an athlete's strength, power, and muscular endurance when conducted immediately before resistance training. And if intensity is decreased, can an athlete get the same adaptations?


In the article linked above, two groups would perform concurrent training with a resistance training and an aerobic training component. One group, however, would also perform maximal effort cycling. It was hypothesized that "combining 3 modes of training (weight training, treadmill running, and maximal-effort cycling) would enhance strength and power."


Standing broad jump was used to assess lower-body power and seated chest press to assess upper-body strength.


The authors' hypothesis was proven incorrect.  The addition of 2 x 10-45s maximal effort cycling had no effect on standing broad jump or chest press. But the authors state, "The most significant piece of evidence supporting the hypothesis was the trend toward improved standing broad jump performance in the SEC group." That trend can be seen here: 



Standing broad jump (cm)

Maybe they would've found statistical significance if they had more subjects.

One key point we can take from this study: concurrent training did result in improvements in power and strength (though not significant). It is unfortunate that there was not a third, non-concurrent training group that only performed resistance training and/or maximal effort cycling to see if the concurrent training groups would improve a similar amount.

One problem I have with this study is that I hardly consider their concurrent training, "concurrent training." The subjects only performed 15:00 of aerobic running per session. For the competitive endurance athlete, 15:00 is not training; 15:00 is a short warm-up. I would like to see 60+ minutes of aerobic work. In total, all the training was completed in 45 minutes, and only done twice a week. I can't help but wonder if this data is applicable to competitive athletes who are training 10 or more hours per week. It only makes sense that adding maximal effort cycling 2x/wk would improve lower body power when the participants are only training an hour and a half a week. But once an athlete begins approaching overtraining or diminishing marginal returns... Then, where can the athlete get the biggest bang for his buck? Concurrent training or non-concurrent training? Same session, or alternate session? And so on...

Saturday, June 1, 2013

Cheap Homebrew Sports Drink

I drink a lot of carbohydrate and electrolyte beverages.

Why?

1. They taste good, so I want to drink them; and drinking more keeps me hydrated.
2. Carbohydrates are a very important energy source for active people -- before, during and after exercise.
3. Glucose promotes water absorption from the small intestine.
4. They also provide electrolytes - promoting water retention and electrolyte balance.

I've tried a lot of them, sometimes forking out more than a dollar per serving for products like Gatorade, Hammer's Heed, PowerBar's Perform, First Endurance's EFS, and so on...

But I've recently started experimenting with making some of my own drinks for performance and recovery. The best thing about making your own drinks is that you can customize it to be any flavor, any concentration (though the consensus is generally that ~6% CHO is the best concentration for gastric emptying and intestinal absorption), and you know and can control exactly which ingredients you put in your drink. Another plus, it can be really cheap.

Today's drink was really satisfying after a hard track workout:

Blueberry Awesomesauce
1 sachet of Celestial Seasonings True Blueberry Herbal Tea ($0.17)
1 scoop GNC Hybrid Carb Complex ($0.14)
1 packet Stevia ($0.06)
1/8 teaspoon sea salt (< $0.01)

Steep the tea bag (of your choice) in boiling water then transfer it to a shaker bottle with the CHO and sea salt and ice. Shake and enjoy. A squeeze of a lemon wedge would go well with it too.

This delicious drink provides 13g of glucose (6% CHO) and 295 mg sodium for just $0.38 a serving. Try it yourself.

Note, you certainly do not have to use the GNC Hybrid  Carb mix. I got it because it was on sale that day, but any unflavored maltodextrin and/or dextrose based carbohydrate powder will work. I've used NOW's Carbo Gain in the past.

Saturday, May 25, 2013

The Female Athlete Triad

I recently presented a short piece on the female athlete triad at school. While it wasn't a particularly thrilling topic to me, I did come across some concerning information. The problem being that there is a lack of knowledge on the issue. From doctors and coaches to the affected women themselves, they need to be made aware of the symptoms and consequences of the triad.

What is the Female Athlete Triad? 
The triad refers to the interrelationships between energy availability, bone mineral density, and menstrual function (ACSM, 2007). Triad, referring to the three aforementioned components exists as a condition when energy availability is insufficient to supply adequate energy for normal physiological processes like menstruation and subsequently maintenance of bone mineral density (BMD).

The diagram below from the American College of Sports Medicine's position stance describes the relationship of the three components of the triad.

When energy availability is kept high, normal menstrual function and optimal bone health are maintained (ACSM, 2007).
Common Signs or Symptoms of the Triad
- Irregular or absent menstrual cycles
- Always feeling tired and fatigued
- Problems sleeping
- Stress fractures and frequent or recurrent injuries
- Often restricting food intake
- Constantly striving to be thin
- Eating less than needed in an effort to improve performance or physical appearance
- Cold hands and feet

So, what's the big deal?
Immediately, decreased bone mineral density leaves an athlete susceptible to stress fractures. But more importantly, for younger adults decreased BMD during young adulthood means they will be more likely to experience osteoporosis and fractures as they age. Further, the BMD that is lost will not be replaced by estrogen replacement therapy, weight gain, or the return of regular menstrual cycles  -- once you've lost it, it may not come back (Burke & Deakin, 2010). Therefore, prevention and early recognition of the triad are crucial to prevent future problems.

Perhaps the most alarming thing about the triad is that most people do not know what it is, the symptoms of it, or its long term consequences. A study from Troy et al. found that in the United States, 52% of physicians, 57% of physical therapists, 62% of athletic trainers and 92% of coaches could not identify all three components of the triad. Of the physicians surveyed, only 9% replied that they were comfortable treating individuals with the triad (2006).

Clearly, there is a lack of knowledge of the topic. So, today I want to try to educate others by providing some information about screening for and preventing the triad.

Prevention
The triad essentially boils down to energy availability. The athlete must consume enough energy to maintain regular physiological processes. Energy availability (EA) refers to the amount of dietary energy remaining after physical exercise. Therefore EA can be calculated as energy consumed minus energy expended during exercise. It is not difficult for most active women to meet EA requirements, but it can be complicated by heavy training or eating disorders.

For maintenance of BMD and reproductive health, a number of sources recommend an EA of 30 kcal/kg fat free mass/day (ACSM, 2007Ihle & Loucks, 2004; Loucks & Thuma, 2003). Applying this rule, a 55kg athlete with 14% body fat -- having 47.3 kg fat free mass (55 - 55*0.14 = 47.3), would need to consume a minumum of 1419 kcal/day before exercising. With an additional hour of running at 8:00/mile (-690 kcals) the athlete is at a minimum of  2109 kcal/day.

The problem with using this equation is that we don't all have DEXA scans or BOD-PODS to know our body fat percentage. Sure, we can estimate. We can also estimate energy expenditure from exercise. The 690 kcals from above came from Vivian Heyward's Advanced Fitness and Exercise Prescription, and is at best another estimate. Why take the time to calculate out EA if two of the variables are just estimates? Then there's the problem of reporting calories consumed. It just isn't practical to measure and record everything we eat every day, and try to calculate caloric intake. Further, if you have an athlete that is at risk for the triad, it is possible she has an eating disorder and she may not report her intake honestly.

A number of studies have demonstrated that appetite is not a reliable indicator of energy availability (Blundell and King, 1998; King et al., 1997;Westerterp et al., 1992). Therefore, “Athletes must learn to eat by discipline to preserve their reproductive and skeletal health” (Burke and Deakin, 2010).

As an Athlete
Instead of focusing strictly on dietary intake, educate yourself and know the symptoms of the triad -- monitor your menstrual cycles, performance, and know that stress fractures may be an indicator of sub-optimal bone health. Seek help from coaches, physicians, nutritionists if you suspect your body weight is too low, you have disrupted menstrual cycles, or any of the symptoms listed above.

Do Not Diet! Without proper supervision of a dietitian or nutritionist. Know that food is fuel for performance and recovery.

The Role of Coaches
Perhaps the most promising form of prevention is educating the professionals working with athletes. It is our job as coaches to be educated, aware, and to monitor our athletes. With that said -- if you work with female athletes, educate yourself on the symptoms of the triad. I strongly recommend reading the ACSM position stand and the IOC's position stand.

 As a coach, if you suspect an athlete to be at risk for developing the triad, screen them for it. If you feel comfortable enough, you can screen them yourself. If not, refer them to a physician that can. The screenings can be verbal or written form and should include questions about the athletes performance, body image, diet, injury status, and menstrual cycles. Below is a list of questions from the IOC's position stand that should be included in a screening.
The Female Athlete Triad, 2006. International Olympic Committee.
If you believe an athlete exhibits symptoms of the triad, refer them to a physician or dietitian for treatment.

Another role of the coach is to encourage athletes to eat for optimal performance, not weight or body image. Of course, coaches should be there for their athletes to encourage them and provide them with positive feedback and support. And finally, coaches should enlist others in treating individuals. Athletic coaches are not generally qualified to treat conditions or prescribe dietary interventions. Therefore, he should have a network of professionals to refer athletes to when needed. Treatment will likely be a multidisciplinary approach enlisting physicians, therapists, nutritionists, etc.

Coaches should also make their athletes aware of consequences of the triad, being diminished reproductive and bone health that can have life-long implications.

The ACSM sums up prevention of the triad in one sentence, "Athletic administrators and the entire health-care team should aim to prevent the triad through education.” If you've read this post, you're off to a good start but this certainly is not a comprehensive guide to the female athlete triad.

References
Blundell, J. E., & King, N. A. (1998). Effects of exercise on appetite control: loose coupling between energy expenditure and energy intake. Int J Obes Relat Metab Disord, 22 Suppl 2, S22-29.

Burke, L., & Deakin, V. (2010). Clinical sports nutrition (4. ed.). New York: McGraw-Hill Medical.

Heyward, Vivian. 2010. Advanced Fitness Assessment and Exercise Prescription. Sixth Edition. 

The Female Athlete Triad. (2007). Medicine & Science in Sports & Exercise, 39(10), 1867-1882.

Ihle, R., & Loucks, A. B. (2004). Dose-response relationships between energy availability and bone turnover in young exercising women. J Bone Miner Res, 19(8), 1231-1240.

King, N. A., Lluch, A., Stubbs, R. J., & Blundell, J. E. (1997). High dose exercise does not increase hunger or energy intake in free living males. Eur J Clin Nutr, 51(7), 478-483.

Loucks, A. B., & Thuma, J. R. (2003). Luteinizing Hormone Pulsatility Is Disrupted at a Threshold of Energy Availability in Regularly Menstruating Women. Journal of Clinical Endocrinology & Metabolism, 88(1), 297-311.

The Female Athlete Triad (2006). International Olympic Committee.

Troy, K., Hoch, A. Z., & Stavrakos, J. E. (2006). Awareness and comfort in treating the Female Athlete Triad: are we failing our athletes? WMJ, 105(7), 21-24. 

Westerterp, K. R., Meijer, G. A., Janssen, E. M., Saris, W. H., & Ten Hoor, F. (1992). Long-term effect of physical activity on energy balance and body composition. Br J Nutr, 68(1), 21-30.

Wednesday, May 22, 2013

Purpose

Vern Gambetta posted last week on ELITETRACK Blogs about how athletes are taught to do drills, but they often go through the motions completing them without purpose, without proper form, or without the power required to get any benefits from the movements.

If you're performing work; whether it's a drill, a hill sprint, or a long run, do it with purpose and set yourself up to nail the purpose of the workout. Recognize that hard work for the sake of working hard is not always good work, but hard work with a specific purpose is the way to winning.

Tuesday, May 14, 2013

More on Hills

Scott Douglas of Runner's World wrote here last month about a new study investigating the effects of various uphill intervals on 5k time trial performance. As a student that has spent some time writing about hill sprints and running economy (RE) and planning a research project on the topic, this little blurb peaked my interest and I've been on the look-out for the publication ever since. Well, it has been accepted for publication but hasn't published just yet. Nevertheless, I have accessed the submitted, unedited version.


Barnes, K. R., Hopkins, W. G., McGuigan, M. R., & Kilding, A. E. (2013). Effects of Different Uphill Interval-Training Programs on Running Economy and Performance. Int J Sports Physiol Perform


An abstract can be found here on PubMed.

To summarize, 15 male and 5 female trained distance runners were evaluated for VO2max, RE, countermovement-jump peak force, and 5k time.  The 20 subjects were then assigned to 1 of 5 groups. Each group completed a specific type of uphill  interval training twice a week in addition to their normal training routine.

Below is a list of the five groups along with a brief description of the intervals they performed.

Group 1 (n = 3) -- 12-24 reps of 8-12s hill sprints, ~60s recovery; 18% gradient

Group 2 (n = 5) -- 8-16 reps of 40-45s, ~ 90s recovery; 15% gradient

Group 3 (n = 5) -- 5-9 reps of 2-2.5 min, ~ 4.5 min recovery; 10% gradient

Group 4 (n = 4) -- 4-7 reps of 4-5 min, ~6-7 min recovery; 7% gradient

Group 5 (n = 3) -- 1-2 reps of 10-25 min, equal recovery; 4% gradient

After completing 6 weeks of training with their respective intervals, the subjects returned to the lab to evaluate VO2max, RE, peak power, and 5k time.

Results:  At best, one group improved their VO2max 4.1%. 5k time was improved ~2.0% (~20s) in all groups. The most interesting piece of information to me is that the group performing the 10s hill sprints showed the greatest improvement in countermovement-jump peak force  (29%) and RE (2.4%). This is the first study to show that hill sprints improve RE. But this study also has some limitations...

First, there was no control group. So, one cannot say that uphill intervals are better than intervals on level-ground -- there is actually some evidence to suggest the opposite.

Second -- Statistical power. With only 3 subjects in a group, seeing a 2.4% improvement in RE, what is the likelihood that their result is not due to an error? I'm not sure, because we are not provided with p values, only percent changes from pre- and post-test measurements; and I am not a statistician. All this means is we cannot be certain that the results seen in this group can be attributed to the intervention (hill sprints); and we cannot definitively say that hill sprints improve running economy.

Third -- Treadmills. It appears that all interval training was conducted on treadmills. I understand the need to standardize speed, gradient, and intensity, but I think there are limitations to treadmill training. Hill sprints for example: hill sprints are balls-to-the-wall effort, not calculated at 120% vVO2max using an equation to extrapolate simulated velocity due to the incline of the treadmill. Just go outside and run up an 18% gradient for 8-10s as fast as possible -- Only then will you get a true maximal effort.

Fourth -- Male and female subjects? We are not told if any effort was made to accommodate for the women's menstrual cycles. Further, we do not know if the five female subjects were evenly distributed among the groups. And who knows? Women may not respond to uphill interval training in the same way men do.

But, despite the limitations of the study, it has shed some light on the topic of hill sprints and running economy and their relationship to 5k performance. In the academic world, we can now say that there is some evidence to suggest that short hill sprints do elicit similar improvements in peak power and RE as plyometrics and resistance training. But it seems coaches and athletes have known this for the last 50 years. It's only fitting that this study came out of New Zealand -- home to one of the pioneers of hill training, Arthur Lydiard.

Another interesting tid-bit from this study is that VO2max was improved the most between groups 3 and 4. Why did these groups see the largest improvements in VO2max? The authors theorize it was because these groups were training at intensities simulating VO2max.

I would like to see a comparison of muscle damage between runners doing level-ground interval training and uphill interval training. Just as coaches have been touting the benefits of uphill running for running economy, they also say uphill running is easier on the legs and may help prevent injuries...

In summary -- uphill interval training may be beneficial for runners. It can improve performance, RE, peak power output, increase stride rate and so on... but then again, so can level-ground interval training...

Monday, May 6, 2013

Fructose, Sucrose, or Glucose?

While I am sidelined with an angry low back today (more on that later), I thought I'd take the time to write a bit about carbohydrates (CHO). Specifically, the different types of CHO and their effects on blood glucose and glycogen replenishment.

CHO ingestion has been found time and time again to aid in intense and prolonged endurance performances. Why? Because two of the mechanisms behind fatigue are decreased blood [glucose] and muscle glycogen content. The two go hand in hand, such that when muscle glycogen is depleted, blood glucose will be metabolized -- and when blood glucose is metabolized and not maintained through ingestion of CHO, blood glucose will drop.

Remember glycolysis? Then you remember glucose is necessary to run glycolysis. And there are two sources of glucose for working muscle cells - glycogen and blood glucose. When an athlete has low glycogen and low blood glucose, his ability to run glycolysis will be limited by CHO availability and exercise intensity will decline (Wright et al., 1991).

Blood glucose - In summary, glucose provides substrate for glycogen synthesis and immediate energy through glycolysis. Keeping blood glucose elevated, or preventing the decline of blood glucose during exercise allows the athlete to maintain a greater intensity while training. Does training at higher intensities elicit greater training responses? No doubt. Could training in a glycogen depleted state improve endurance performance? Maybe, maybe not... I am doubtful. It may depend on the athlete's goals, but note there was no difference in the one variable that matters here -- cycling performance.

It's a lot like the research I've been working on lately with David Morris at ASU. Which yields greater performance gains? Hypoxic or hyperoxic training? Can training with hyperoxic gas (60% O2) improve time trial performance at a simulated altitude of 14,000 ft? Hyperoxic gas enables the athletes to train at a higher work rate (as does training with saturated glycogen stores) on the bike and training at a higher work rate may elicit a greater training response. Further, can training with hyperoxic gas improve TT performance more than training with hypoxic gas (13% O2). The decreased oxygen content significantly reduces the work rate the athletes can sustain during training (like training in a glycogen depleted state) -- but might they get other adaptations from training at altitude? Our preliminary results are intriguing.

But, getting back to maintaining glycogen stores: To maintain training intensity, how can one keep glycogen stores and blood glucose high?


Take a look at the figure above and note, it all boils down to carbohydrate intake. But not all carbohydrates are the same. Muscle metabolizes glucose, and that glucose comes from a number sources in the diet:


     1) Glucose and/or glucose polymers
     2) Fructose, sucrose, galactose, and other sugars not glucose
     3) Amino Acids
     4) Fatty Acids
     5) Alcohol

Blood Glucose
As you might have guessed, numbers 3,4, and 5 are not favorable substrates for raising or maintaining blood glucose levels -- but they can be converted to glucose in the liver in dire situations. Fructose is similar. Fructose cannot be metabolized by working muscle as fructose. Instead, it must be transported to the liver and converted to glucose.  But, some of that fructose will not be converted to glucose. Some of it may be converted to lactate. Not only can conversion of fructose to lactate increase blood [lactate], the CHO available to working muscles will be lower than if the same amount of glucose had been ingested. Note, I lumped sucrose with fructose, because it is not technically glucose. Sucrose is a disacharride made of one molecule of  fructose bound to one molecule of glucose. Despite being 50% glucose, when the same amount is consumed, sucrose will not elevate blood glucose as much as glucose alone (Murray et al., 1989).

Insulin
Another problem with fructose and sucrose is that they do not stimulate insulin secretion to the degree of glucose does -- even when equal amounts are consumed. This will be more important following exercise, when insulin is need to help transport glucose into muscle cells and activate glycogen synthase.

Absorption Rate
Further, glucose has a faster intestinal absorption rate (and helps with water absorption). Glucose is actively transported out of the small intestine. Fructose, however, must be passively absorbed -- delaying intestinal absorption rate, and possibly leading to gastric distress. (Murray et al., 1989)

In summary - glucose is the superior form of CHO to ingest in and around exercise. It is actively transported out of the gut, it raises blood glucose directly and can be metabolized by working muscle immediately, and after exercise, it is a better secretagogue of insulin - enabling transport into muscle cells, activating glycogen synthase and restoring glycogen more rapidly than other forms of carbohydrate (Murray et al., 1989; Bowtell et al., 2000).

What does this mean for the athlete?
     When training, pass on the sodas, pass on the fruit juice, pass on the Powerade... And go for the drinks that contain maltodextrin, glucose, dextrose, and maltose.

References


Bowtell, J. L., Gelly, K., Jackman, M. L., Patel, A., Simeoni, M., & Rennie, M. J. (2000). Effect of different carbohydrate drinks on whole body carbohydrate storage after exhaustive exercise. J Appl Physiol, 88(5), 1529-1536. 

Murray, R., Paul, G. L., Seifert, J. G., Eddy, D. E., & Halaby, G. A. (1989). The effects of glucose, fructose, and sucrose ingestion during exercise. Med Sci Sports Exerc, 21(3), 275-282.

Wright, D. A., Sherman, W. M., & Dernbach, A. R. (1991). Carbohydrate feedings before, during, or in combination improve cycling endurance performance. J Appl Physiol, 71(3), 1082-1088. 

Saturday, March 23, 2013

Concurrent Strength and Endurance Training

     You know exercise can change your body. Through exercise, one can change parameters such as body composition, endurance capacity, maximal strength, efficiency, etc. The basis behind these changes is that the stress of exercise causes adaptations to occur in the body. The rule of specificity tell us these adaptations are specific to the training stimulus (Hickson).  For example, the most effective way to increase a muscle’s maximum strength would be to specifically train that muscle through short-duration, high intensity resistance training, not through prolonged, low resistance repetitive contractions. Conversely, endurance based athletes like marathon runners or long distance cyclists, should train specifically for their endurance events by training over prolonged amounts of time with a lower sustainable resistance or work rate. With this said, how should athletes in events that require a mixture of strength and endurance train? Employing a training regime combining strength and endurance training may yield the best results, but research indicates that for maximum strength gains, the two types of training should not be done in the same session, or even the same day.
     First, let’s discuss these two types of training. Strength training is generally an activity of short-duration done a very high or maximal intensity. These exercises, such as weight training or plyometrics, increase one’s capacity to do high-intensity, high-resistance work. Some athletes rely more on high-intensity, high-resistance work than others. For example, the general goal of football players, powerlifters, and sprinters is to generate as much force as possible for short periods of time. Following the rule of training specificity, these athletes should train specifically for their respective high intensity event that requires rapid, high-force generation and the best way to do this is by strength training. Through strength training, athletes improve their strength by learning how to recruit, or signal, more motor units. Additionally, those motor units recruited at high thresholds trigger larger, faster, higher force generating fibers. Further, by recruiting more motor units, more fibers are recruited, more fibers contribute to the effort and more force can be generated by the muscle(s). Strength training also results in muscle cell hypertrophy. Hypertrophy is an increase in muscle size or volume. This increases the number of contractile proteins in the muscle cells and enables the muscles to generate more force.
     At the opposite end of the spectrum, endurance athletes do not rely primarily on high-power movements. Instead an endurance athlete’s performance relies strongly on his aerobic capacity. This is the ability of one’s body to take in and use oxygen. An increase in endurance performance may result from an increase in VO2max, or the maximal rate that oxygen can be taken up and delivered to the muscle cells. Improvements in maximal muscular force generation will not play much of a role in endurance events.  Adaptations from endurance training include increased heart stroke volume, increased mitochondrial and capillary density as well as increased aerobic enzyme content in muscle cells. These adaptations directly increase the body’s ability to deliver oxygen and produce ATP aerobically.
     But what about events in the middle of the strength-endurance exercise continuum? Sports such as short to middle distance running (400m - 5000m), track cycling, and swimming, rely on both strength and endurance adaptations. Logically, one might think that combining the two types of training would yield favorable results; and he would be right to a degree. But recently research has shown that through concurrent strength and endurance training, athletes do not get the same benefits as they would if they separated their strength workouts from their endurance based workouts. One study found that same day, compared to alternate day, training impaired strength development in one repetition leg press tests. The authors of the study found that both the subjects that alternated strength and endurance training and the subjects that did concurrent training sessions increased their one repetition leg press max, but the group that alternated days had a significantly greater increase. 
     The authors offered a few theories that could account for this phenomenon. One theory was that they believed the quality or the volume of the strength training session was reduced following endurance training. The reduction in quality was due to already fatigued muscles. Alternatively, the volume of the strength training session was also reduced when it was done prior to endurance training because the athletes were anticipating a strenuous endurance training session and did not want to fatigue themselves before a long and difficult training bout (Sale et al).
     Another proposed theory for the inhibition of strength gains through concurrent training is the theory of overtraining.  Overtraining occurs when the volume and intensity of an individual's exercise exceeds their recovery capacity. It is generally characterized by a decrease in athletic performance. One study showed strength declined during the ninth and tenth weeks of concurrent training. The author believed the mechanism behind the decrease was overtraining because the participants were training 80 minutes per day (Hickson). Deeply connected with the overtraining theory is the theory of low muscle glycogen.   Much like overtraining, low muscle glycogen results from the inability of glycogen stores to replenish themselves from session to session. Chronically low glycogen stores could impair subsequent workouts, especially high intensity exercise. Athletes training more strenuously or frequently are more likely to experience overtraining or glycogen depletion and these states will impair recovery from exercise sessions reducing the favorable adaptations (Nader).
     Dudley and Djamil found that concurrent training reduced the magnitude of the increase in muscular strength in high-velocity low-force contractions, but did not alter the magnitude of the increase in high-force low-velocity contractions. Previous studies had proven high-speed low-resistance exercises would increase muscle strength at that same high speed. Here, the combination of training negatively affected the said adaptation. This means that concurrent training did not affect low-speed strength, but decreased the favorable adaptation to high-speed contractions. This adaptation would not be favorable to a middle distance, combined strength and endurance athlete because these athletes rely on fast explosive movements. Dudley and Djamil’s proposed theory was that the resistance component of concurrent training negatively affects the adaptation that would normally be seen with high intensity endurance training on a neural level (Dudley, Djamil). But it should be noted this proposal has not been proven and there is little evidence to suggest that endurance training negatively affects recruitment of fast-fatigable motor units (Nader, 2006).
     Another, and what I find to be the most interesting mechanism behind the incompatibility of concurrent training occurs on a molecular level. Biochemical and genetic based studies have revealed that muscle cells have specific cellular regulatory process that can be induced or hindered by certain forms of exercise. Resistance and endurance training activate different signal pathways that initiate different responses from muscle cells. Studies show that acute resistance exercise activates a signaling pathway that in turn increases protein synthesis (see figure 1). This increase in protein synthesis leads to hypertrophy of muscle cells thus increasing the force they can generate. Conversely, aerobic exercise activates another signal pathway that increases metabolic adaptations favorable to endurance exercise.  Endurance exercise stimulates AMPK, an important energy regulator in skeletal muscle (figure 2). Recent studies show that the two signal pathways have antagonistic effects on each other. This means that the activation of AMPK from aerobic exercise inhibits protein synthesis (Nader).
Figure 1. Resistance training activates IGF/Calcineurin Pathway which activate mTOR and leading to hypertrophy. Slide from Morris 2012.
Figure 2. Decreases in Glycogen, CP, and ATP (from endurance training) activates AMPK and inhibits mTOR - inhibiting hypertrophy. Slide from Morris 2012.

     There is a number hypotheses as to why concurrent training may result in less than optimal adaptations for strength gains and possibly aerobic efficiency. Regardless of the varying hypotheses, all of the studies have one thing in common: that concurrent strength and endurance training is not as effective as separated training when the goal is improving strength, hypertrophy, or rate of force development. After reviewing this research, it appears that it would be most beneficial for the athletes participating in events that combine strength and endurance components to arrange their workouts into separate sessions. This way they can reap the benefits of both their strength and endurance training.
     But while there is substantial evidence to suggest that aerobic training inhibits hypertrophy, there is still little evidence demonstrating that endurance training negatively effects motor unit recruitment when done concurrently with strength training. Yes, Dudley and Djamil found that force of high speed contractions was limited -- but this study also recruited 14 untrained college aged women. Hakkinen found that rate of force development was limited, but here again this study recruited a number of untrained women. In the end, I believe the jury is still out on concurrent training. While it may inhibit strength gains from hypertrophy, I still think improvements can be made in the weight room through improved recruitment. Additionally, by recruiting these fast-fatigable motor units and fast twitching fibers again and again -- are they not being trained? Can they not improve their glycolytic and/or aerobic capacities? After all, once the slower muscle fibers become fatigued, won't the faster fibers will be recruited to get the job done?
     What the evidence tells us: If your goals are hypertrophy and strength gains -- stick to the weight room. If your goal is improved strength, power, and middle/long distance running performance -- perhaps separate sessions (and periodization?) are the way to go. Additionally, there has been much debate over whether distance runners should lift low weight with high repetitions or high weigh twith low repetitions. The bottom line, the heavier the weight, the greater force output required, the more motor units recruited. I leave you with a Flotrack video of Galen Rupp in the weightroom: Rupp WOW Rupp's results speak for themselves.

Further reading:
http://www.elitetrack.com/article_files/neuromuscularadaptations.pdf
http://sriechman.tamu.edu/629/2012/Nader%202006.pdf
http://sriechman.tamu.edu/629/2012/hickson%20interferance%201980.pdf
http://rodrigoborges.com/principal/pdf/forca_18.pdf

References

Dudley, Gary A., and Rusdan Djamil. "Incompatability of Endurance- and Strength-Training Modes of Exe

rcise." Journal of Applied Physiology 59.5 (1985): 1446-51. Web. 8 Nov. 2010. <http://rodrigoborges.com/pdf/forca_18.pdf>.

Hickson, Robert C. "Interference of Strength Development by Simultaneously Training for Strength and Endurance." European Journal of Applied Physiology 45 (1980): 255-63. Web. 17 Nov. 2010. <http://www.springerlink.com/content/g5462621u3011433/fulltext.pdf>.

Nader, Gustavo. "Concurrent Strength and Endurance Training: From Molecules to Men." Medicine & Science in Sports & Exercise 38.11 (2006): 1965-70. Web. 4 Nov. 2010. <http://journals.lww.com/acsm-msse/Fulltext/2006/11000/Concurrent_Strength_and_Endurance_Training__From.13.aspx>.  

Sale, D.G., et al. "Comparison of two regimens of concurrent strength and endurance training."Medicine & Science in Sports & Exercise 22.3 (1989): 348-56. Web. 5 Nov. 2010 <http://journals.lww.com/acsm msse/Abstract/1990/06000/Comparison_of_two_regimens_of_concurrent_strength.12.aspx>.

Thursday, March 14, 2013

An Athlete's Pantry - Supporting Ingredients

I'm taking a step away from exercise performance and physiology this week to talk about another love in my life: Food.

I often find myself in the grocery store grabbing the most essential of the essentials: Milk, bread, eggs, meat, cereal... For me, it's usually easy to pick the main entrees for the week -- Say... curry, chicken breasts, chili, steak, pasta, etc. The hardest thing is deciding on what sides items to cook, and remembering what supporting ingredients you need.

For those times it helps to have a few things stockpiled in your fridge and pantry. That way, if you forgot an ingredient, you might already have it. And if you don't -- maybe you can still throw something together with those stockpiled ingredients. I think my girlfriend Courtney and I do a pretty good job managing our fridge and pantry.

What do we keep on hand?

Rice - An excellent carbohydrate source, easy to cook, stores well
Beans - black, pinto, chickpea, lentils - pair well with rice, decent protein source, good starch, hearty, "musical fruit"
Tomato products - diced, sauce, paste, pasta sauce, ketchup - stores well, versatile, useful for a number of recipes
Pasta - Great carbohydrate, quick and easy side or entree
Couscous - see Pasta
Eggs - incredible and edible, cheap, good protein, a must for many baked goods  
Flour - did somebody say baked goods?
Sugar - for coffee, desserts, baked goods, oatmeal, some recipes
Oats - oatmeal, cookies, muffins, good carbohydrate
Peanut butter - a guilty pleasure or a quick fix lunch or snack, satisfying, can also make good sauces
Spinach - versatile, easy, nutritious vegetable
Carrots - easy snack, versatile in entrees and sides
Olive Oil - extra virgin, please
Greek Yogurt - plain - from smoothies to tzatziki, delicious and nutritious
Frozen peas and corn - for soups, or as an ice pack
Dried fruit - raisins, cranberries, apricots, figs, dates - quick and easy snack, versatile and a good carbohydrate source
Juice - liquid fruit, right? Not quite, but juice is still a quick source of carbohydrates, tastes good, and has some nutritional value
Mustard - sandwiches, BBQ, slaw, baked beans, marinades - love me some mustard
Onions - an essential ingredient in many recipes, buy in bulk
Garlic - see onions 
Lemons/limes - it just needs something... like lemon! 
Potatoes - mashed, baked, in soups, broiled, versatile, great carbohydrate, delicious
Sweet potatoes - mmm... see potatoes - excellent source of vitamin A
Bell pepper - another versatile vegetable - take 'em roasted, in salad, stir-fry, chili, etc.
Celery - to complete the cajun "Holy Trinity" - great flavor, some people like it for a snack...
Butter - an old time essential
Spices - because some foods can be quite boring without any spice - you know what you like, stock up; they'll keep forever

Tonight, using my on-hand ingredients, I threw something together and it turned out really well. But don't take my word for it...

Moroccan Chickpea Salad:
Makes 2 - 3 servings

1 Tbsp olive oil
1 can chickpeas - drained
1/2 bell pepper - diced
1 carrot - finely diced
2 cloves garlic - minced
1/2 cup frozen corn
1/2 cup frozen peas
Juice from 1/2 lemon
1 tsp oregano
1/4 tsp cardamom
Salt to taste

Heat oil in pan, sautee the bell pepper and carrot together, add garlic, corn, and green peas and sautee 3- 5 minutes over medium heat. Add chickpeas, lemon juice and season with oregano and cardamom. Salt to taste.

This picture can't do it justice...

Serving size = 1/2 recipe
FAT: 9 g
CHO: 64 g
PRO: 18 g

I split this into 2 large servings and put it along side some salmon and couscous. All together, it took me about 10 minutes and cost about $2 a serving. Just one example of how a well stocked pantry can keep you healthy, wealthy, and efficient.

Monday, March 4, 2013

Physiology of Lactate Threshold and Practical Applications to Training

All right, now that we've briefly covered the basics of lactate metabolism, let’s move on to training for lactate production, transportation and oxidation.

Production, of course, refers to the creation of lactate through glycolysis. And remember, to be able to create lactate, glucose must be present (from blood glucose or cleaved from glycogen) to run glycolysis. So to create lactate, an athlete needs to engage in training that relies on glycolysis for ATP production, in turn creating H+ and lactate. Again, lactate is not the molecule we need to buffer or transport out of the cell. It is the H+ that accompanies lactate that disrupts glycolysis and muscle contraction. H+ must be transported out of the muscle cells by monocarboxylate transporters (MCTs). These are H+-Lactate co-transporters, meaning H+ and lactate must be present before they are both pumped out of the cell together into extracellular space. Then the lactate and H+ may diffuse into the bloodstream.

When the H+ and lactate diffuse into the bloodstream, the H+ will be buffered by phosphates and bicarbonate. See below:

\rm CO_2 + H_2O \rightleftarrows H_2CO_3 \rightleftarrows HCO_3^- + H^+

Reading the equation from right to left, increasing [H+] in the plasma will consume a proton to create carbonic acid (H2CO3). Applying Le Chatelier's principle, we know that decreasing [CO2] will enable this reaction to proceed to the left. That is one reason why ventilation increases dramatically (ventilatory threshold) near lactate threshold (to purge the blood of CO2 to buffer the H+ created from very high rates of glycolysis).

Because of this buffering mechanism, we see relatively constant plasma pH values with increasing intensities, and increasing [lactate]. But eventually, with high enough intensities, the buffering mechanisms become overwhelmed and plasma pH drops. This is known as acidosis. It has been argued that pH threshold is a better indicator of performance than lactate threshold (Morris and Shafer, 2010). Here you can see, the difference in power outputs at the two different thresholds:


pH is indicated by magenta markers, [Lactate] is indicated by the blue. Notice, the pH threshold in these subjects (240W) falls long after the lactate threshold is met (200W). This further demonstrates that it is not the accumulation of lactate that contributes to acidosis, rather it is H+. Morris did, however, find that pH threshold and lactate threshold are significantly correlated to 20 km time trial performance; meaning, the higher power output at lactate threshold (LT) or pH threshold, the faster the time trial performance. The same can be said for running performance – the faster an athlete can run before lactate accumulates, the faster that athlete will be able to complete a bout – indicating a need for high lactate thresholds, or high work rates with less reliance on glycolysis.

To raise an athlete’s LT, training can be approached from a multitude of angles, but two of the most utilized workouts are tempo runs and intervals. Tempo runs or lactate threshold runs are generally done at paces/workrates just slower than or equivalent to LT – often referred to as maximal lactate steady state (MLSS), or just LT. Sometimes you will hear coaches talk about anaerobic lactate threshold runs - these are just sustained 10-20:00 runs done just above lactate threshold pace. Training at paces/workrates greater than LT – also called supramaximal or intensive intervals are shorter bouts of higher intensity training separated by bouts of recovery.

An example of the first workout is a steady 40:00-60:00 @ LT pace, whereas an example of a supramaximal session would be something like 8-12 x 1:00-3:00 at >100% LT with 1:00-3:00 recovery. Physiologically, the responses to the two workouts are very different from one another – blood lactate concentration during the 40:00-60:00 LT run may remain relatively constant between 3 – 6 mmol/L, whereas lactate values during the supramaximal intervals may be as high as 20+ mmol/L.

Looking at these values, one might assume that “more is better” and supramaximal intervals must stress the system more because they invoke higher lactate values. But consider the time of the bouts – keeping in mind recoveries after the shorter supramaximal intervals. While the shorter intensive intervals may cause higher spikes in blood lactate, they are short lived. And by completing extensive intervals or steady runs near LT, blood lactate concentrations will remain relatively low, but over a longer period of time. So, which will make you faster? Arguably, both. But which is best?  Well, it depends.

Graph 96, from Peter Janssen’s book Lactate Threshold Training, demonstrates lactate responses to the respective types of training. Admittedly, this graph is a bit over simplified – but it gets the point across. Intensive (supramaximal) intervals elicit high [lactate] but can only last so long (1:00 - 3:00). Whereas longer extensive repetitions (3:00 - 10:00) elicit lower [lactate], but an athlete can sustain them over longer period of time. And finally, intensive endurance (MLSS, marathon pace) runs elicits even lower [lactate], but can be sustained for a substantially longer period of time (20:00 - 60:00).



Training to maximize lactate threshold or pH threshold is no easy task.  There are multiple ways to approach the issue when it comes to types of workouts and timing of workouts in preparation for a season or championship race.

First, a coach or athlete must recognize the specific demands of the goal race because specificity is important when choosing the types of workouts an athlete should run. A 1500m is much different in terms of energy demands from a half marathon. Lactate values during a 4:00 1500m may reach >15 mmol/L whereas lactate values during a 65:00 half marathon may be closer to 4-6 mmol/L. And since lactate threshold has been found to be closely correlated with pH threshold (Morris and Shafer, 2010), it’s safe to assume that intramuscular/plasma pH falls lower during 1500m running than it does during a half marathon.
With that said, and with the rule of specificity in mind – training for the respective events should mimic their demands. 1500m runners should engage in high-intensity training to create large amounts of lactate. But if exercise continues (without recovery periods or rest) the athlete will experience a decrease in intramuscular pH and eventually the exercise will cease. Remember Table I from Cairns (2006):


In this review, Cairns demonstrates that short high intensity exercises do indeed elicit the greatest decrease in muscle pH. The lowest values found here were after 20 minutes of 30-40s repeated sprints, and during maximal exercise lasting from 1.5 to 11 minutes. Unfortunately, I cannot access reference 21 to look up the repeated sprint exercise protocol.

It’s nothing profound, but this data indicates that these exercises best mimic the demands of the 1500m run – and a 1500m runner would be wise to run intervals of 30s to 11 minutes. But wait, 11 minutes? That’s a long interval. And remember, these were maximal efforts – running a workout consisting of multiple 11 minute intervals at a maximal effort just isn’t feasible. That’s because a drop in pH (acidosis) inhibits glycolysis, inhibiting ATP production in subsequent bouts. Therefore, a 1500m runner is better off completing 2 sets of 6-8 x 60s with 60-75s recovery and 3:00-4:00 active recovery between sets.

By incorporating active recovery into the workout, lactate is transported out of the glycolytic muscle cells along with those hydrogen ions (by the MCT co-transporters). The H+ ions will be buffered by bicarbonate, and lactate can either be transported to the liver to be converted back into glucose, or transported by MCT1 into oxidative (slower twitching) muscle fibers and utilized for ATP production in the Krebs cycle and then oxidative phosphorylation. So, what you see with recovery is a decrease in lactate, and increase or maintenance of intramuscular/plasma pH. Because intramuscular pH is maintained with adequate recovery, glycolysis is not inhibited and the athlete can complete more work: more sets or reps. In this case, instead of completing 11 minutes in one bout, the athlete can complete 12-16 minutes of work at or near the same workrate or pace.

As for completing longer 40+ minute LT runs - I do not believe these are appropriate for 800/1500m runners because they are not specific in terms of pace or energy demands. No, 40:00 LT runs should not be difficult for 1500m runners, but that does not mean they should do them. Running 40:00 at a pace near LT, you get relatively low lactate values (maybe 4-6 mmol/L) - which do not replicate the >10 mmol/L that will be seen during 1500m running. Additionally, during the relatively prolonged slower pace 40:00 run, the athlete will not be recruiting the faster twitching glycolytic fibers to the same degree that will be called upon during a 1500m race. This is not to say that 1500m runners should never complete 20-40 minute LT runs. But these types of workouts should be saved for recovery cycles, or early introductory periods.

The same goes for cyclists – except cyclists can generally complete more extensive workouts than runners because of the absence of eccentric muscle contractions.

Not only can you get more work out of your workouts with adequate recovery, but the recovery can also train the MCT co-transporters and slower twitching muscle fibers. Because high intensity exercise creates large amounts of lactate, it will also increase the number of MCT4 co-transporters so that more lactate and H+ can be transported out of the glycolytic fibers. Further, high intensity exercise has also been shown to increase MCT1 (Juel and Halestrap, 1999). MCT1 transports lactate and H+ into slower twitching oxidative muscle fibers. Here, lactate dehydrogenase can convert lactate back into pyruvate to be converted to acetyl Co-A and oxidized it in the krebs cycle. So in a way, your slow twitching fibers become hydrogen buffers and lactate "recyclers."

But what about our half marathoner? The guy running for 65:00 at roughly lactate threshold. Could he also benefit from high intensity intervals? You bet! By increasing lactate and H+ clearance from glycolytic fibers, they’ll be able to function at a higher capacity for a longer period of time. Additionally, by increasing the number MCT1 co-transporters, he’ll be better able to buffer H+ and use it and lactate as fuel in his slower twitching oxidative fibers. But, with that said it is still important to keep event specificity in mind. High intensity intervals are not the be-all and end-all. A 65:00 half marathoner likely does, and should do high intensity interval training, but he may do them less frequently than the 800m, 1500m, or 5000m runner. Additionally, his intervals should be longer and slower than those of the 1500m runner to emphasize specificity. A main-set for this half marathoner may be 5-6 x 2k at 100-105% LT (5:00 – 4:45/mile) with 60-120 sec. recovery. The recovery to work ratio here does not need to be as high as it would be for the 1500m running his workout because running within 5% of LT should not cause an accumulation of H+ that would inhibit glycolysis.

I’ve mentioned a couple of examples of workouts for middle and long distance runners, but through the course of a season or build to an important race we don’t want to have the athlete complete the same workout again and again. I believe the athlete needs some variety, and a change in training stimulus to continue to improve.  And it can get complicated when developing a training plan – depending on whose coaching methodology you follow, or what you believe in terms of periodization and progression. A number of coaches (Jack Daniels, David Morris, Brad Hudson, Joe Friel, and Arthur Lydiard) prescribe shorter, higher intensity bouts early to midway through in the training phase – even for the marathon runner or long distance cyclist.

These short high intensity intervals can work to raise LT by increasing the number of MCT co-transporters while potentially building strength and improving recruitment through faster running. These high intensity interval workouts are not high in volume so that the short intensive interval sessions can also serve as primers for longer more extensive workouts. After completing 6-8 weeks of training with a mix of high intensity intervals when our half marathoner goes to run his steady 40:00-60:00 LT run or 3-4 x 2 mile interval workout, he can actually maintain a higher pace (and still be running at LT) than he would if he had not completed the intensive training early in the training period because he can transport, buffer H+ and utilize lactate. Late in the training phase, half marathoners and marathoners should incorporate more and more of the pure LT running with 40:00 - 60:00 @ LT or long broken LT intervals because they are more specific to their respective events.

And that's about all I have to say about that. I'm sure I'll think of something I left out later.

References

Cairns Simon P. Lactic Acid and Exercise Performance Culprit or Friend? Sports Med 2006.

Janssen, Peter. Lactate Threshold Training. 2001. Human Kinetics.

Juel C., Halestrap AP. Lactate transport in skeletal muscle – role and regulation of monocarboxylate transporter. J Physiol 1999;517;633-642

Morris DM, Shafer RS. Comparison of power outputs during time trialing and power outputs eliciting metabolic variables in cycle ergometry. Int J Sports Nutr Exerc Metab 2010; 20(2):115-21