Q & A: Anaerobic Workouts and Energy Drink Ingredients

Dear Speed Lab,
What is your opinion on incorporating anaerobic sessions into an endurance-training plan? Is this type of training going to be harmful or helpful to my performance? Many professionals in a variety of endurance sports include this type of training in their training plans.

Daniel Schlader
Louisville, Ky.

Dear Daniel,
One of most fundamental rules of training is specificity, which states that your training should replicate the demands of the specific event you're training for. The rule of specificity arises because different events tend to rely on different energy systems in the body (which need to be specifically trained) and also because many disciplines require a specific set of motor skills and neurological adaptations.

However, the reality is that while endurance sports draw heavily on the aerobic energy system in competition, they do sometimes perform short, high-energy bursts (e.g. sprinting for the line) that rely on pathways that are often neglected in training because of the need to concentrate on endurance performance training.

And new findings by a team of Finish scientists at the Research Institute for Olympic Sports suggest that neglecting to train for anaerobic performance may be counter-productive for endurance athletes, and that anaerobic performance can be enhanced without increasing training volume or compromising endurance.

In the study1, the effects of concurrent explosive strength and endurance training on aerobic and anaerobic performance and neuromuscular characteristics were studied in 25 endurance runners. These runners were split into an experimental group (13 runners) and a control group (12 runners).

All runners trained for eight weeks with the same total training volume, but in the experimental group 19 percent of the endurance training was replaced by explosive-type training, which included sprints and strength drills. After the eight-week training program, all the runners were evaluated for various aspects of performance with the following results:

The maximal speed during a maximal anaerobic running test and 30-meter sprint speed improved in the experimental group by 3.0 and 1.1, respectively, compared to the control group. The concentric and isometric forces generated during leg extension increased in the experimental group but not in the control group.

The experimental group improved their muscular force-time characteristics and had rapid neural activation of the muscles (i.e. they were able to generate more power through more rapid muscular contractions). The increase in thickness of the quadriceps muscles after eight weeks was nearly double in the experimental group compared to the control group.

Importantly, the maximal speed during an aerobic running test, the maximal oxygen uptake (VO2max) and running economy (how efficiently the runners used oxygen for any given running speed) remained unchanged in both groups.

The implications of these research findings are clear: If you are an endurance athlete whose event also demands brief bursts of high-intensity work, substituting some of your endurance training (up to 20 percent) with anaerobic work may not cause a drop in aerobic performance, and may even give you a competitive edge.

What Goes Into Energy Drinks?

Dear Speed Lab,
It seems like a lot of new energy drinks on the market are adding glutamine and branched-chain amino acids to their beverage. What's your take on this? Is there a benefit in terms of performance?

David Perry
Baton Rouge, La.

Dear David,
There are often suggestions that the addition of ingredients other than the conventional sports drink ingredients may enhance the efficacy of sports drinks, and a variety of different amino acids have been proposed. Among these are glycine, glutamine and branched-chain amino acids (BCAA).

Glycine and other actively transported amino acids offer the prospect of enhancing the rate of intestinal water uptake. However, the limited data available do not support this proposition2.

Glutamine can act as an energy substrate for cells of the immune system. Plasma glutamine levels may fall after intense exercise, leading to the proposal that glutamine supplementation may enhance immune function in athletes during periods of hard training.

Although this is an attractive hypothesis, the available evidence does not support it and well-controlled studies of glutamine supplementation have failed to show a beneficial effect3. The lack of stability of glutamine in an acid solution would also seem to be an insuperable difficulty to its addition to sports drinks.

The addition of BCAA to sports drinks is based on the central fatigue hypothesis. The theory proposes that an increased uptake of tryptophan (TRY), the amino acid precursor to the neurotransmitter serotonin, into neurons located in the brain is associated with increased susceptibility to fatigue in the periphery (i.e. the muscles).

The BCAA compete with TRY for uptake into the brain, and it is argued that increasing BCAA availability will decrease brain TRY uptake and thus reduce the subjective sensation of fatigue. Well-controlled laboratory trials of BCAA supplementation, however, do not support an ergogenic effect4.


1. J. Mikkola, H. Rusko, A. Nummela, T. Pollari and K. Häkkinen. (2007). Concurrent Endurance and Explosive Type Strength Training Improves Neuromuscular and Anaerobic Characteristics in Young Distance Runners. International Journal of Sports Medicine, 28: 602-611.

2. Shi, X., Summers, R. and Schedl, H. P et al. Effects of carbohydrate type and concentration and solution osmolality on water absorption. Medicine & Science in Sports & Exercise. 27: 1607-15, 1995.

3. Rohde, T., MacLean, D. A., Pederson, B. K. Effect of glutamine supplementation on changes in the immune system induced by repeated exercise. Medicine & Science in Sports & Exercise. 30: 856-62, 1998.

4. van Hall, G., Raaymakers, J. S., Sarris, W. H. and Wagenmakers, A. J. Ingestion of branched-chain amino acids and tryptophan during sustained exercise in man: failure to affect performance. Journal of Physiology (Lon). 486: 789-94, 1995.

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