FACTORS AFFECTING BAR KINEMATICS AMONG WOMEN PERFORMING THE FREE WEIGHT BENCH PRESS

Abstract

Research focused on elite male lifters using near maximal lifts and a preferred grip width during the bench press (BP) has provided insight useful for instruction and equipment design. With increased popularity of the BP among women, understanding their bar kinematics is important for optimizing the BP as part of a regular fitness program. PURPOSE To compare sagittal plane bar kinematics between experienced and novice female lifters using varied loads and grip widths during the free weight BP exercise. METHODS 12 female volunteers (age range 18–26 y) were classified as either experienced (n = 6) or novice (n = 6) based on familiarity with the BP. One week after determining 1RM, each subject performed the BP under 6 time-controlled and randomized conditions of varied load (60% and 80% 1RM) and grip widths (narrow, neutral and wide). Five trials in each condition were recorded (60 Hz) to provide 3D kinematics. Dependent variables consisted of 5-trial mean values of bar kinematics at specific instants of the ascent phase in the superior/inferior (SI) and anterior/posterior (AP) directions. Three-way mixed factor ANOVAs (load × grip × skill level, α = .01) were used for data analysis. RESULTS The kinematic-time profiles were similar between the skill levels across load and grip conditions, but there were magnitude differences. Position and acceleration variables exhibited more skill by grip interactions and main effects than did the velocity measures. In general, experienced lifters exhibited greater bar displacement and acceleration in the SI and AP directions, with differences greatest using the narrow grip. CONCLUSION Skill level, load and grip width interact to affect bar positioning and acceleration during the BP performed by women. Supported by Illinois State University and a Jump Rope for Heart grant from the Illinois Association of Health, Physical Education, Recreation and Dance.