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by Thomas Kurz
The following question is about not overdoing work on cardiovascular endurance with a young girl. Although specifics of the answer are for cardiovascular endurance, the principle of using physiological measurements and signs of good well-being to adjust training to the athlete’s current adaptability applies to work on all physical abilities in all athletes.
I have started working with an elite 12-year-old female soccer player. She has played in an international tournament with a 12-year-old boys’ team and plays with 14-year-old girls. The big goal for her is cardiovascular endurance for both sustained efforts and ability to burst. I would like to get your input and also discuss risk of hormonal imbalance due to low body fat percentage from cardiovascular work. I am not sure if you have come across this while training junior athletes.
I have never trained soccer players, so all I can offer are generalities. Here they are:
The standard method of developing endurance for long-duration efforts and for burst, such as the finishing kick, is doing both intervals and longer runs, in separate workouts and in the same workout (most of the time intervals first, followed by longer and slower runs). Length of the interval: up to the distance you need to sprint. Rest periods and number of reps: such as to keep every rep good. Length of the longer run: as long as the running form is good. Pace of the longer run: up to what is needed in the event. Number of reps in case of repeating the distance: minimum needed to make desired progress.
Regarding risk of hormonal imbalance: What is bad for one system or even one organ is bad for them all and will show up in basic physiological measurements (see the chapter “Measurements and Tests” in Science of Sports Training), in common signs of good well-being (good sleep, good mood, etc.), and in muscle activity tests. So, if all is well then there is nothing to worry about. Verify this with an endocrinologist or, if available, a sports medicine internist.
If training intensity is beyond the athlete’s current adaptation potential, then you will see it first in mood changes and sleep disturbances. Then the athlete will become jumpy and easily startled. (Looking at reactions to sudden stimuli is my standard tool to see who is overtrained or about to be.) The excessive intensity may show up in an ECG as changes in T-wave (flat or double peak or plateau at the peak–info from an article by Butchenko et al. in Teoriya i Praktika Fizicheskoy Kultury, 1989, vol. 1, no. 18-19). If you see symptoms of excessive training intensity, workout loads should be changed from intensive to extensive loads. So instead of several intense workouts per day, do one of long duration (up to two hours) but low intensity. When the athlete’s mood and vital signs return to normal, the intensity of work can be increased.