Brief power activities lasting for 30 to 60 seconds or repetitive sprint events rely on energy stored in the muscles as ATP and creatine phosphate (CP). Weight lifters and sprinters will gear their training towards improving those energy systems. As duration extends beyond one minute, energy is provided by anaerobic glycogen dependent pathways which produce lactic acid as a byproduct. And finally, after several minutes, aerobic pathways take on increasing significance with well over 90% of the energy in endurance events coming from these oxygen dependent metabolic systems. A successful training program focuses on developing the energy system specific for your particular event.
The muscle groups needed for your event should also be factored into training program development. When 60 college aged men, equal as far as their level of aerobic conditioning, were divided into three groups - one training on a treadmill, one on a bicycle trainer at an equivalent %VO2max, and a third used as a non training control, the exercise specific benefits of training were clearly demonstrated. Both training groups improved their VO2max equally when tested on their training device, however, while the treadmill group improved 7% in VO2max when tested on either the treadmill or bicycle ergometer, the group training on the bicycle trainer improved 8% when tested on the bicycle ergometer, but only 3% when tested on the treadmill - proof of the failure of crosstraining to maximize performance across all aerobic events. The investigators speculated that changes in metabolic and circulatory factors in the muscles being trained, or adaptations related to the total muscle mass used during training, were responsible for these differences. Thus a successful training program also needs to focus on the specific activity and muscle groups to be used in the event.
PRINCIPLES OF TRAINING
All training programs adhere to basic, common principles. They include:
I. EXERCISE OVERLOAD - the training event must increase the frequency, intensity, or duration of the specific exercise activity being trained for to be able to promote physiologic improvement and achieve a training response.
II. SPECIFICITY OF TRAINING - adaptations in metabolic pathways and muscle fibers are dependent on applying the types of metabolic stress (aerobic versus anaerobic) to be used in the final event to the specific muscle groups to be used for that activity.
III. SPECIFICITY OF VO2MAX - To achieve the optimum improvement in VO2max for any activity, the cardiovascular system needs to be stressed by that specific activity. As demonstrated above, there are general benefits to the heart and vascular system from any aerobic exercise, but if one wants to maximize VO2max, one needs to use the specific activity in training (a bicycle trainer will not maximize performance on a treadmill).
IV. SPECIFICITY OF LOCAL MUSCLE CHANGES - there are local improvements in the muscle trained for a specific activity that will not generalize to other muscle fibers in that limb, or to the same muscle used in other exercises. Changes in ATP levels and other metabolic parameters in the vastus lateralis (a thigh muscle) are greater in cyclists (who use this muscle to a greater degree) than in runners training at the same VO2max).
V. INDIVIDUAL DIFFERENCES - Not all individuals will respond to an equivalent training stimulus to the same degree or at the same rate. We are all different genetically and training programs need to be individualized.
VI. REVERSIBILITY OF TRAINING - Deconditioning can occur rapidly when training ceases. At bed rest for 20 days, there is a decrease in VO2max of about 1% per day. Maintaining some level of conditioning during the off season minimizes deconditioning. And a reconditioning program should be part of every athletes schedule before the next season’s competition begins.