The Effects Of Maximum Voluntary Isometric Contraction On 1rm Performance In The Bench Press

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 no studies have examined the acute, selective fatigue of the primer movers at 90 degrees of elbow flexion on the bench press exercise. PURPOSE: The purpose of this study was to determine if Maximum Voluntary Isometric Contraction (MVIC) at 90 degrees of elbow flexion would affect performance in the bench press exercise. 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 difference (p=0.020) was found between treatments by paired sample t-test analysis. The standard group (60.95kg±18.83) significantly out performed the isometric group (53.0kg±11.48). CONCLUSION: It is apparent from the findings of this study that preferential fatigue of the prime movers at 90 degrees of elbow flexion acutely reduces performance in the bench press exercise. This suggests that strengthening the muscles at this joint angle through training may have the potential to increase strength in the bench press exercise.