Archive for the ‘specificity’ Category

Understanding Interval Training

February 19, 2009

Stephen Seiler has a nice description of what happens in your muscles when you undergo interval training. It really serves to illustrate the differing physiological responses that come about with different durations at any given intensity. It also serves as a reminder as to why you don’t want to go 110% all the time (hint: optimal stimulus for cardiac stroke volume improvement is not the same as that required for widespread capillary growth and oxidative enzyme upgregulation.)

One interesting take on the article, if you look at the data he presents, is that you can have your cake and eat it too, if you exercise strict discipline. If interval duration is kept short enough, you can accumulate many minutes of time at faster than race-pace velocities while keeping the concentration of lactic acid in your muscles about what it would be at a more moderate, steady-state pace. The advantage of introducing that sort of training is that you work on neuromuscular efficiency as well as increasing oxidative capacity of type IIa muscle fibers.

Notice from the data, however, that if you ‘overcook’ the interval duration by even 60 seconds, the lactate concentration can almost double. You cross from a zone where you are training your cells to upregulate pyruvate dehydrogenase, an enzyme that aids in speedy aerobic metabolism, to a no-man’s land where you neither optimally stimulate aerobic or anaerobic metabolic pathways.

Cycling (and cross-country skiing for that matter) are aerobic sports, so next time you work out, give some thought about your specific goals for the day. Are you trying to improve stroke volume? Then go flat out for 3 minute intervals that hurt like the dickens. Do you want to raise your velocity at LT, the number one determinant of endurance performance? Then remember the lessons from the Seiler article and give your muscles the conditions they need to adapt.

Power Training To Increase Performance

February 6, 2009

This paper, by researchers in Finland, examines the link between neuromuscular power and running economy. What’s interesting to note here is that runners improved 5k performances without a corresponding increase in VO2max. However, the neuromuscular improvements associated with power training made them more efficient runners at race paces, and thus faster overall.

It seems that any quality training program should include some emphasis on power development. This would be especially true for cycling, which requires a high loading of the vastus lateralis and the ability to maintain high power for long periods of time.

 

Paavolainen, Leena, Keijo Ha¨ kkinen, Ismo Ha¨ – 

ma¨ la¨ inen, Ari Nummela, and Heikki Rusko. Explosive- 

strength training improves 5-km running time by improving 

running economy and muscle power. J. Appl. Physiol. 86(5): 

1527 – 1533, 1999training, whereas the development of maximal O2 

uptake (V˙ O2 max) is not influenced as much (e.g., Refs. 

10, 16, 18, 22). These observations are mainly based on 

experiments in which heavy-resistance strength train- 

What makes this study interesting is that it deals with trained athletes whom presumably have already attained a fairly high VO2max as a result of prolonged training. It would be interesting to compare the training program used in the study with a control group that performed short intervals at slightly faster than race pace for comparison. If neuromuscular adaptations are most specific to both the force and frequency of movement, then it would stand to reason that intervals at slightly higher than race pace would be at least as effective, perhaps even more, at decreasing 5k times.

Muscle Fiber Adaptation Varies Depending on Workload

February 5, 2009

This article goes more in depth regarding the adaptations you see in skeletal muscle with various workloads. Notice the principle of specificity at work.

Human skeletal muscle fiber type adaptability to various workloads

RS Staron, RS Hikida, FC Hagerman, GA Dudley and TF Murray

Muscle biopsy specimens were removed from the vastus lateralis muscles of three groups of human subjects: controls, weight lifters, and distance runners.