VERTIMAX: Clinical Studies

As Published in the June 2008 Issue of the National Strength & Conditioning Journal

Abstract

New training devices such as the VertiMax resisted jump trainer are marketed as a means of improving lower body reactive power. The purpose of this study was to evaluate the effectiveness of the VertiMax, in combination with traditional training modalities, for improvements in lower body power among highly trained athletes. Forty men and women Division I collegiate athletes representing the sports of baseball, basketball, soccer, gymnastics, and track completed a 12-week mixed-methods training program. Two groups were constructed with both groups performing conventional resistance training and weightlifting exercises. The training control group performed traditional plyometric exercises while the experimental group performed similar loaded jump training on the VertiMax. Lower body power was measured before and after the training program by the TENDO® FiTROdyne Powerlizer, and statistically compared for differences between groups. Data analyses identified a significant (p < .05), and meaningful difference between power development among the two groups, with the VertiMax eliciting a 5-fold greater treatment effect (ES = .54) over conventional resistance and plyometric training alone (ES = .09). These data convincingly demonstrate that the VertiMax represents an effective strategy for developing lower body power among trained college athletes, when combined with traditional strength and conditioning approaches.

Background

The inclusion of explosive lifting as a primary training tenet is done so to stimulate neuromuscular adaptation, supporting the enhancement of muscular rate of force development (RFD) and peak power output. Despite proven efficacy to promote such specialized adaptations, many professionals have abandoned traditional explosive lifting techniques, citing safety concerns and/or inefficient time expenditure.

In an effort to supplement/replace traditional approaches, various training technologies and prescription innovations have been devised to elicit similar muscular power adaptation. Overloading a vertical jump may be a superior means for development of rate of force production and peak power output, as execution is not heavily contingent on technique, thus enabling athletes of various backgrounds to productively train.

Introduction and Purpose

Evidence has suggested that combining heavy resistance training with high speed exercises may be the optimal technique for eliciting neuromuscular adaptation to support both the stretch reflex and RFD, as well as for improvement in a variety of performance variables concerned with maximum strength and power.

Independently, heavy resistance-low velocity training, as well as low resistance-high velocity training may effectively generate improvements at the high force end of the force–velocity curve and toward the high velocity end of the force-velocity curve, respectively. In combination, it is plausible that training for strength, power, and speed may elicit a robust synergistic effect, and maximize neuromuscular development for peak power output and explosive athletic performance. Failure to optimize each of the basic force producing characteristics of the neuromuscular and musculoskeletal systems may diminish the developmental-potential of muscular power adaptation, and expression across a continuum of high force and high speed movements.

The purpose of this investigation was therefore to examine the effects of a concurrent mixed methods training protocol supplemented with loaded jump training using the VertiMax, compared to a traditional resistance/plyometric training regimen, on jumping ability and peak power output in collegiate athletes.

Methods

Forty college athletes (30 m, 10 f) representing the sports of baseball, basketball, soccer, track, and gymnastics were divided into two groups (equated by sport): Vertimax and Control. Both groups performed conventional resistance training for the lower body involving squats, power-cleans, and lunges three times per week for 12 weeks. The only difference in the training protocols was the inclusion of additional plyometric exercises on the Vertimax performed solely by the Vertimax group.

Athletes were tested before and after the 12-week program for lower body power using the Tendo Fitrodyne Powerlizer which measures power output (watts) based on the athletes’ body weight and speed of movement during a counter-movement vertical jump test. Changes in power were compared using an Independent-Samples T-test and effect sizes were calculated using pre/post means and standard deviations.

Results

Independent samples T-test identified significant differences between control group and Vertimax group at baseline; therefore, comparison of change in power (pre-post) was conducted. Data demonstrated a significantly greater increase in power in the Vertimax group as compared to the control group. Effect size calculations demonstrated a 6 times greater treatment effect in the Vertimax group.

Discussion

These data clearly demonstrated an added benefit of performing loaded jump training exercises on the VertiMax, in conjunction with traditional preparatory strength and conditioning modalities, when compared to strength/power training alone. Since the only difference in training between groups was the use of the VertiMax device, the statistical difference in power improvement may be attributed entirely to the supplementary VertiMax jump-training.

The athletes recruited for this study were very familiar with conventional sports conditioning methods, such as was employed with the control group. For athletes who are very accustomed to traditional body-weight explosive modalities, conventional plyometric exercises may not provide adequate overloading stimuli.

Practical Application

A unique feature of the VertiMax is the ability to apply progressive resistance to plyometric jumps. The added resistance, along with the ability to alter and progress the resistance over time, could certainly be expected to enhance the stimulation of the neurological system and adaptations in the areas of activation and synchronization.  An additional benefit of the VertiMax exercises is the specificity of such training to explosive power exerted in sport-specific movement. Athletes are able to perform their own individualized jumping technique, while at the same time, face a significant external resistance.

Table 1: Group Statistics (n = 20 each group)