EFFECT OF IN-SEASON TRAINING ON BODY COMPOSITION AND BENCH PRESS STRENGTH OF COLLEGIATE WOMEN TRACK SPRINTERS
by<
Megan M. Mosher and Danielle D. Peterson
Human Performance Laboratory, Truman State University, Kirksville, MO

Original Publication Information:
IAHPERD Journal Volume 30. No.2 Spring, 1997.

INTRODUCTION
Body composition and strength are very important considerations in a track athlete's training regimen. This is especially true among female track athletes where the additional fat load may negatively affect performance. The intense training programs of these athletes have specific physiological effects relative to the events in which they participate. The endurance training of distance runners tends to result in low body mass and low body fat content with little effect on strength development. Sprinting may also produce low body fat content but may enhance the development of lean body mass (LBM), resulting is a greater total body mass. Sprint training also may enhance strength development.

To optimize performance, the athlete may wish to reduce body fat content while increasing muscle strength through various training methods. Weight training has become popular as a means of achieving these results. However, many female athletes are concerned that weight training will overdevelop muscle mass and produce a masculine physique, although this is not supported by research (Terbizan, 1996). The purpose of this study was to assess the change in body composition and muscular strength resulting from four months of intense training for track and field participation.

METHODS
Seven college women sprinters (age = 19.9 y) were tested for body composition and 1-RM bench press strength before and after four months of intense in-season training. Skinfold measurements were taken at the triceps, suprailiac, abdominal, thigh, knee, and calf sites. The averages of three measurements at each skinfold site were used to predict body density using a population-specific equation (Mayhew et al., 1983). The %fat was calculated from the Siri conversion (1956). Lean body mass (LBM) was calculated using %fat and body mass.

The 1-RM bench press was determined using standard Olympic free weights. Each athlete had experience in weight training which reduced the learning effect (Johnston et al., 1993). Prior to 1-RM testing, each athlete was allowed to warm up by lifting light weights. When the subject was ready for the test, spotters assisted in lifting the bar from the support rack. The subject lowered the bar slowly until it touched the chest and returned it to the full-arm extended position. If the lift was successful, weight was added and another attempt given after a 3-4 minute rest. The greatest weight lifted correctly was designated as the 1-RM. The 1-RM was usually achieved in four or five trials.

RESULTS
A paired t-test revealed a significant reduction in body fat content following training (Table 1). However, there was no significant change in LBM or total body mass. The 2.3% decrease in body weight was due mainly to a 7.1% decrease in relative fat content. The 1-RM bench press decreased nonsignificantly by 3.5% over the training period, which was similar to the decrease in body mass. When the 1-RM bench press strength was expressed relative to body mass, the decreased was only 1.1% (Table 1). However, when strength was expressed relative to LBM, there was no decrease.

The correlations between pretraining and posttraining values for body mass, LBM, and strength/kg LBM were high (Table 1), indicating consistent change with training among these factors. The correlation between pretraining and posttraining %fat was somewhat lower, indicating less consistency in changes from the beginning to the end of the training period.

The correlation between 1-RM and LBM at the pretraining test (r = 0.92) was reduced somewhat at the posttraining test (r = 0.74), possibly indicating more variability in these scores after training. Correlations between %fat and bench press strength were moderate at both the pre-training (r = 0.52) and post-training (r = 0.56) testings.

* Significant at p<0.05.

Table 1. Changes In Body Composition And Strength In College Female Track Sprinters Durning Four Months Of Training (n= 7).

Pretraining
Variable Mean SD Mean SD % Delta t r
Body Weight (kg) 57.7 5.6 56.4 5.5 - 2.3 1.91 0.95
Lean Body Mass (kg) 47.9 4.2 47.6 4.2 - 0.6 0.80 0.96
% Fat 16.8 1.7 15.6 1.1 - 7.0 2.97* 0.74
1-RM Bench Press (lbs) 115.0 20.6 110.7 19.0 - 3.7 1.16 0.88
Bench Press/kg 0.90 0.10 0.89 0.10 - 1.1 0.48 0.81
Bench Press/kg LBM 1.05 0.13 1.05 0.12 0.0 0.66 0.98

DISCUSSION
Intense competitive training for track sprinting altered body composition in the current subjects mainly by reducing body fat content. There was no muscle mass gain during this period. This pattern is different from that seen in volleyball and basketball players measured over four years of competitions (Terbizan, 1996). The rationale for the lack of gain in LBM is most likely due to the lower levels of testosterone in most females compared to males.

One factor which could have affected the changes noted in the current subjects was their initial fitness level. Those athletes who began the training in better physical condition had less potential to change over the course of the four months. Since most college track athletes train year round, it is possible that the major changes experienced by these athletes occurred during the Fall training period from September until January. Although not substantiated by research findings, antidotal evidence seems to indicate that female athletes experience more weight fluctuations during a year than to their male counterparts.

Unfortunately no measures of running performance were available for comparison with body composition and strength changes. It is possible that the loss in body fat and the maintenance of LBM could offset the slight loss of strength leaving running performance unaffected. Perhaps other factors such as eating habits and genetic makeup of each athlete may contribute to the changes in overall body composition and strength realized during training.

REFERENCES