Excessive training

With excessive training, either or both volume of training and intensity of training are increased to extreme levels. The “more is better” philosophy drives the training schedule. For many years, athletes were undertrained. As coaches and athletes became bolder and started to push the envelope by increasing both training volume and intensity, they found that athletes responded well, and world records began to tumble. However, one can only take this philosophy so far. At a certain point, performance begins to either plateau of decline. Let’s take a look at some examples of this.

Most of the research on excessive training has been conducted on swimmers. For that reason, the material in this section concerns swimmers, but it alos applies to most other forms of training.

One can increase training volume by increasing either the duration or the frequency of training bouts. But does increased volume translate into increased performance? Research shows that swim training 3 to 4h per day, five or six days each week, provides no greater benefits than training only 1 to 1.5h per day. In fact, such excessive training has been shown to significantly decrease muscular strength and sprint swimming performance.

Few studies have compared the physical conditioning and performance benefits of single versus multiple daily training sessions. Studies conducted thus far reveal no scientific evidence that multiple daily training sessions enhance fitness and performance more than a single daily session. This is illustrated in the picture below, which show the responses of two groups of swimmers who trained once per day(group 1) or twice per day(group 2) for a period of six weeks during a 25-week training program. All swimmers began the program following the same training regimen: one time per day. But from the beginning of the 5^th week through the end of the 10^th week, group 2 increased its training to twice per day. After six weeks on the different regimens, both groups returned to once-daily program. All the swimmers’ heart rates and blood lactate values decreased dramatically when training began, and no significant differences were seen in the two groups’ results in response to the change in training volume. The swimmers who trained twice per day showed no additional improvements over those who trained only once per day. In fact, their blood lactate concentrations(figure a) and heart rates(figure b) appeared to be slightly higher for same fixed-pace swim.

To determine the influence of long-term, excessive training, performance improvements of swimmers who trained twice daily for a total distance of more than 10,000m(10,936yd) per day(the LS, or long-swim group) were compared with improvements of those who swam approximately half that distance in a single session each day(SS, or short-swim, group). Changes in performance time for the 100yd(91m) front crawl were examined over a four-year period for both groups. The LS swimmers and SS swimmers experienced an identical average improvement of 0,8% per year. Similar findings also were observed for competitors in other events, such as the 200, 500, and 1,650yd(183, 457, and 1,509m) front crawl.

The concept of training specificity implies that several hours of daily training will not provide the adaptations needed for athletes who participate in events of short duration. Most competitive swimming events last less than 2 min. How can training for 3 to 4h per day at speeds that are markedly slower than competitive pace prepare the swimmer for the maximal efforts of competition? Such a large training volume prepares the athlete to tolerate a high volume of training but likely does little to benefit actual performance.

The need for long daily workouts(high volume) is now being seriously questioned by researchers. For certain sports, it appears that training volume could be reduced significantly, possibly by as much as one-half in some sports, without reducing the benefits, and with less risk of overtraining athletes to the point of decreased performance. The principle of training specificity suggests that low-intensity, high-volume training does not improve sprint-type performance.

Training intensity is also an important factor and refers to both the relative force of muscle action(i.e., resistance training) and the relative stress placed on the metabolic and cardiovascular system(i.e., anaerobic and aerobic training). There is a strong interaction between training intensity and training volume: as intensity is reduced, training volume must be increased to achieve adaptation. Training at very high intensities requires substantially less training volume, but the adaptation that occur will be significantly different from those achieved with low-intensity, high-volume training. This concept applies to all three types of training, that is, resistance, anaerobic and aerobic.

High-intensity, low-volume training can be tolerated only for brief periods. While this type of training does increase muscular strength in resistance training and total body speed and anaerobic capacity in high-intensity interval training, it provides little or no improvement in aerobic capacity. Conversely, low-intensity, high-volume training stresses the oxygen transport and oxidative metabolic systems, causing greater gains in aerobic capacity, but has little or no effect on muscular strength, anaerobic capacity, or total body speed.

Attempts to perform large amounts of high-intensity training can have negative effects on adaptation. The energy needs of high-intensity exercise place greater demands on the glycolytic system, rapidly depleting muscle glycogen. If such training is attempted too often, for example daily, the muscles can become chronically depleted of their energy reserves, and the person might demonstrate signs of chronic fatique or overtraining.