The effects of velocity-spectrum training on the ability to rapidly step.

Falls may occur because of a deficiency in the ability to rapidly step in the desired direction. Previous models developed to predict rapid step ability have been based on balance, video analysis, or uniplanar isokinetic performance. The purpose of this investigation was to determine the effects of multiplanar velocity-spectrum training of the hip. Seven males (23.14 years) and 16 females (23.75 years) were tested for peak torque, peak power, and rate of velocity development and on rapid step test (RST) measurements. Participants in the training group went through 8 training sessions over 4 weeks, consisting of unilateral hip flexion/extension and hip abduction/adduction of each leg, while the control group maintained regular activity throughout the 4-week span. Exercises were performed on a Biodex System 3 isokinetic dynamometer beginning at a speed of 60 degrees x sec(-1), gradually increasing in speed every week up to 180, 300, and 400 degrees x s(-1), respectively. Analysis of the data revealed no significant (p < 0.05) differences between groups on any measure. However, the data showed a significant improvement in RST time (pre: 50.87 +/- 4.41 seconds; post: 49.20 +/- 4.28 seconds) and number of errors (pre: 4.13 +/- 2.87 errors; post: 2.75 +/- 1.81 errors), implying that a learning effect took place on the RST for all individuals. Additionally, short-term isokinetic training did not translate into significant results. It was concluded that 4 weeks of velocity-spectrum training of the hip did not lead to improvements on the ability to rapidly step, as measured by the RST. Therefore, the open-kinetic-chain training should not be done for improvements on a functional, closed-kinetic-chain activity.