The Relationship Of Arm Span To Maximum Voluntary Isometric Contraction And 1rm Bench Press Performance.

Abstract

In previous studies, isometric lifting has produced varied results. These studies have examined both the acute and training effects of isometric contraction on the bench press. To date there have been no published studies that account for arm length on the acute affects of isometric contraction on the bench press exercise. PURPOSE: The purpose of this study was to determine what the relationship between arm span and the acute effects of Maximum Voluntary Isometric Contraction on one repetition maximum performance in the bench press. METHODS: The participants involved in this study were eight female college track and field athletes (Height 1.72m±0.9, BMI 32.1±9.2) who compete in the throwing event (Hammer, Shot Put, Discus, Javelin). The average 1RM bench press for the participants was 59.5±19.8 kilograms. A counterbalanced, within subjects design was chosen for this study. Participants were asked to report to the weight room on two separate occasions. Both days began with a standard warm-up of the bench press exercise consisting of 70% 1RM for a set of five repetitions and 80% 1RM for 3 repetitions. After the warm-up both trial days consisted of three separate, single maximal attempts to set a new 1RM in the bench press. The two treatments that were counterbalanced were Standard (STAND) and MVIC. The STAND treatment consisted only of the three maximal lifts in the bench press exercise. The MVIC treatment consisted of a 30 second maximal voluntary isometric contraction against a stationary bar at 90 degrees of elbow flexion immediately prior to each single maximal bench press lift to induce fatigue. A 72 hour washout period was incorporated between treatments. RESULTS: A significant bivariate correlation (r=-0.855, p=.007) was found between arm span and change between previously determined 1RM and performance during MVIC. No significant relationship was found between arm span and performance change in the STAND condition (r=-.344, p=0.404). CONCLUSION: The significant negative correlation suggests that those individuals with longer arm spans were not able to lift as much weight post-MVIC. Thus the fatigue associated with MVIC produced a greater affect in those who displaced the weight the farthest past 90 degrees of elbow flexion.