The Effect Of A Seven Week Lifting Program On Electromechanical Delay In Female Collegiate Track Athletes

Abstract

The purpose of this study was to investigate the effect of various strength training techniques on series elastic component skeletal muscle as measured by elctromechanical delay. A seven week strength training program employing a plyometric type exercise, (ie. catch I throw) was compared to programs employing standard triceps extension lift and a ballistic medicine ball throw with no counter movement. Ten collegiate female track and field athletes, who competed in the sprints and jumps, signed informed consent and were randomly assigned to one of three test groups. All subjects participated in their normal 7 week, 3 x per week weight training program, plus one additional exercise for the triceps. Group 1 (n=3) performed a standard triceps extension (3 sets of 12) at a weight appropriate for their program. Group 2 (n=4) performed an explosive throw with a 2 kg medicine ball with no counter movement (3 sets of 12) using only the triceps from the same body position as the triceps extension. The 3rd group (n=3) performed a plyometric exercise of the triceps with a 2 kg medicine ball (3 sets of 12). All subjects performed maximal velocity elbow extensions on command from a relaxed state against a threshold force (TF) apparatus set to release at 8, 22, 27, and 36 pounds. Five trials were collected at each setting. Simultaneous triceps EMG and wrist acceleration data were collected at 780 Hz via Metrabite AID card, to a digital computer system and stored for later analysis. Subjects were tested 2 days before the start of the lifting program and again within 1 week after completion of the program. Electromechanical delay latencies (EMDL), defined as the time between onset EMG and first acceleration of the wrist, were calculated, and mean values for each test condition, for each test session were determined. Subjects were grouped by lifting technique and a MANOVA Repeated Measures design was employed for statistical analysis. Results of the statistical analysis showed significant differences in EMDL at the four TF levels (p=.Ol). No significant pre/post differences at any TF level, and no pre/post - TF interaction were shown.