John C. Garner

Changes in physical activity and fitness after 3 months of home Wii Fit™ use.

Owens, SG, Garner III, JC, Loftin, JM, van Blerk, N, and Ermin, K. Changes in physical activity and fitness after 3 months of home Wii Fit™ use. J Strength Cond Res 25(11): 3191–3197, 2011—The purpose of this study was to examine changes in physical activity and fitness variables in members of 8 volunteer families after 3 months of home use of the Wii Fit™ interactive video game. Pre and postintervention measurements were obtained from 21 subjects relative to physical activity (5 days of accelerometry), aerobic fitness (graded treadmill test), muscular fitness (push-ups), flexibility (sit-and-reach test), balance (composite equilibrium score), and body composition (body mass index and % body fat). Use characteristics of the Wii Fit™ device were also determined. A series of 2 (age group) × 2 (time) repeated measures analyses of variance were conducted to assess changes over time and between adults and children. Three months of home Wii Fit™ use revealed no significant age group × time interactions or main effects of group or time for daily physical activity, muscular fitness, flexibility, balance, or body composition. An age group × time interaction (p = 0.04) was observed in peak &OV0312;O2 (ml·kg−1·min−1) with children displaying a significant (p = 0.03) increase after 3 months of Wii Fit™ use, whereas adults showed no significant (p = 0.50) change. Daily Wii Fit™ use per household declined by 82% (p < 0.01) from 21.5 ± 9.0 min·d−1 during the first 6 weeks to 3.9 ± 4.0 min·d−1 during the second 6 weeks. Most measures of health-related fitness in this exploratory study remained unchanged after 3 months of home use of the popular Wii Fit™ whole-body movement interactive video game. Modest daily Wii Fit™ use may have provided insufficient stimulus for fitness changes.

A comparison of the effects of 6 weeks of traditional resistance training, plyometric training, and complex training on measures of strength and anthropometrics.

MacDonald, CJ, Lamont, HS, and Garner, JC. A comparison of the effects of six weeks of traditional resistance training, plyometric training, and complex training on measures of strength and anthropometrics. J Strength Cond Res 26(2): 422–431, 2012—Complex training (CT; alternating between heavy and lighter load resistance exercises with similar movement patterns within an exercise session) is a form of training that may potentially bring about a state of postactivation potentiation, resulting in increased dynamic power (Pmax) and rate of force development during the lighter load exercise. Such a method may be more effective than either modality, independently for developing strength. The purpose of this research was to compare the effects of resistance training (RT), plyometric training (PT), and CT on lower body strength and anthropometrics. Thirty recreationally trained college-aged men were trained using 1 of 3 methods: resistance, plyometric, or complex twice weekly for 6 weeks. The participants were tested pre, mid, and post to assess back squat strength, Romanian dead lift (RDL) strength, standing calf raise (SCR) strength, quadriceps girth, triceps surae girth, body mass, and body fat percentage. Diet was not controlled during this study. Statistical measures revealed a significant increase for squat strength (p = 0.000), RDL strength (p = 0.000), and SCR strength (p = 0.000) for all groups pre to post, with no differences between groups. There was also a main effect for time for girth measures of the quadriceps muscle group (p = 0.001), the triceps surae muscle group (p = 0.001), and body mass (p = 0.001; post hoc revealed no significant difference). There were main effects for time and group × time interactions for fat-free mass % (RT: p = 0.031; PT: p = 0.000). The results suggest that CT mirrors benefits seen with traditional RT or PT. Moreover, CT revealed no decrement in strength and anthropometric values and appears to be a viable training modality.

Impact on balance while walking in occupational footwear

Hazards and challenges present in the workplace pose a number of potential balance risks for injuries and illness. Purpose: The purpose of the study was to examine the differences in balance while walking for extended durations with different types of occupational footwear. Methods: Participants were tested for balance prior to walking session (Pre) and then again every 30 minutes until the 240th minute in three types of occupational footwear; work boots, tactical boots and low top shoes. Sway velocity and root-mean-square sway in the anterior-posterior and medial-lateral directions were evaluated using a 3 × 9 repeated measures analysis of variance to identify any existing differences within exposure time and footwear types. Results: Significant differences in postural sway were found over time in medial-lateral sway and between footwear in anterior-posterior and medial-lateral sway. Significant differences were found between the work boots, tactical boots and low top shoes, with the low top shoes exhibiting an increased postural sway. Conclusion: The changes in balance over time may be attributed to the workload placed on the individual resulting from the extended durations of walking/standing. Use of low top shoes resulted in a relatively greater balance decrement. The work boots and tactical boots despite having a greater mass, resulted in less of a balance decrement, which may be attributed to their elevated boot shaft height.

The influence of occupational footwear on dynamic balance perturbations

Occupational footwear is designed for safety and have been shown to impact balance, especially in occupational environments, where the human body is subjected to destabilizing forces by both internal and external perturbations. Purpose: The purpose of the study was to analyze the effects of three industry standard occupational footwear on balance performance during external perturbations. Methods: Thirty-one healthy male adults (age: 21.2 ± 1.4 years; height: 179 ± 9.4 cm; mass: 82.6 ± 15.4 kg) with no history of neuro-musculoskeletal abnormalities participated in this study. The experimental procedure followed a repeated measures design; all participants were tested for balance with barefoot (BF), and three occupational footwear presented in a randomized order: low top shoe (LT), tactical boot (TB) and work boot (WB) on the same day separated by 10-minute washout rest periods. Balance was assessed by Motor Control Test (MCT) on the NeuroCom Equitest with synced electromyography (EMG) recordings from right lower extremity muscles. Postural response latencies, EMG mean, peak, %maximal voluntary contraction and time-to-peak muscle activity were analyzed using a one-way RM ANOVA individually for backward and forward perturbations (p = 0.05) and followed by pairwise comparisons with a Bonferroni correction. Results: Postural response latencies were significantly faster with barefoot. Although no differences existed for response latencies between LT, TB and WB, the TB demonstrated significantly lower muscle activity during balance perturbations. Conclusion: Under acute conditions, even though postural response latencies were faster in barefoot condition, use of tactical boot had normal response latencies and also demonstrated significantly lower muscle activity, suggesting the need for only minimal requirement of muscular effort to maintain balance when exposed to external perturbations.

Walking on ballast impacts balance

Railroad workers often perform daily work activities on irregular surfaces, specifically on ballast rock. Previous research and injury epidemiology have suggested a relationship between working on irregular surfaces and postural instability. The purpose of this study was to examine the impact of walking on ballast for an extended duration on standing balance. A total of 16 healthy adult males walked on a 7.62 m × 4.57 m (25 ft × 15 ft) walking surface of no ballast (NB) or covered with ballast (B) of an average rock size of about 1 inch for 4 h. Balance was evaluated using dynamic posturography with the NeuroCom® Equitest System™ prior to experiencing the NB or B surface and again every 30 min during the 4 h of ballast exposure. Dependent variables were the sway velocity and root-mean-square (RMS) sway components in the medial–lateral and anterior–posterior directions. Repeated measures ANOVA revealed statistically significant differences in RMS and sway velocity between ballast surface conditions and across exposure times. Overall, the ballast surface condition induced greater sway in all of the dynamic posturography conditions. Walking on irregular surfaces for extended durations has a deleterious effect on balance compared to walking on a surface without ballast. These findings of changes in balance during ballast exposure suggest that working on an irregular surface may impact postural control. Practitioner Summary: Epidemiology and scientific literature indicate a conceivable connection between walking surface characteristics and injury. These potential links are particularly evident in the railroad industry given the ballast surfaces widely encountered. The current findings provide data in which to enhance current work practices focusing on postural instability.

Slip initiation in alternative and slip-resistant footwear

Slips occur as a result of failure of normal locomotion. The purpose of this study is to analyze the impact of alternative footwear (Crocs™, flip-flops) and an industry standard low-top slip-resistant shoe (SRS) under multiple gait trials (normal dry, unexpected slip, alert slip and expected slip) on lower extremity joint kinematics, kinetics and muscle activity. Eighteen healthy male participants (age: 22.28 ± 2.2 years; height: 177.66 ± 6.9 cm; mass: 79.27 ± 7.6 kg) completed the study. Kinematic, kinetic and muscle activity variables were analyzed using a 3(footwear) × 4(gait trials) repeated-measures analysis of variance at p = 0.05. Greater plantar flexion angles, lower ground reaction forces and greater muscle activity were seen on slip trials with the alternative footwear. During slip events, SRS closely resembled normal dry biomechanics, suggesting it to be a safer footwear choice compared with alternative footwear.

Impact of alternative footwear on human balance

Alternative footwear are those that are most commonly used for casual or recreational purposes, over the course of the day. The purpose of this study was to examine the effects of three forms of alternative footwear (thong style flip-flops, clog style Crocs®, and Vibram Five-Fingers®) on balance with a low-intensity workload. Eighteen healthy male adults (age: 22.9 ± 2.88 years; height: 179 ± 6.0 cm; mass: 81.3 ± 8.8 kg) participated in this study. Balance performance along with electromyographic (EMG) measures was assessed with sensory organization test (SOT) and motor control test on the Neurocom Equitest, while donning alternative footwear, prior to and after a one-mile walk at a self-selected pace. Sway velocities and root-mean-square sway, SOT equilibrium scores, postural response latencies, and EMG measures from lower leg muscles were analysed using a 3 × 2 (footwear × time) repeated-measures ANOVA. Results from balance variables revealed a significant main effect difference for footwear in the eyes closed and eyes open sway-referenced vision conditions and a significant main effect difference for time in the eyes open, eyes open sway-referenced vision, and eyes open sway-referenced platform conditions. Pairwise comparisons revealed MIN demonstrating significantly greater balance performance in the pretest condition and the post-test demonstrating significantly lower balance performance. Greater balance performance from MIN could be attributed to the barefoot design suggesting an increase in somatosensory feedback from the plantar surface, particularly during absent or conflicting visual feedback. The lower balance performance seen in post-test could be attributed to the one-mile walk, suggesting that even a transient physiological workload could be sufficient to cause balance decrements in alternative footwear.

A Brief Review: Using Whole-Body Vibration to Increase Acute Power and Vertical Jump Performance

SUMMARY INCREASED VERTICAL JUMP (VJ) AND PEAK POWER (PP) ARE ESSENTIAL IN MANY SPORTS. USING WHOLE-BODY VIBRATION (WBV) BEFORE A VJ MAY ENHANCE JUMP HEIGHT AND PP OUTPUT AS INDICATED BY PREVIOUS RESEARCH. HOWEVER, VARIATION IN WBV PLATFORMS, FREQUENCIES, AMPLITUDES, EXPOSURE TIMES, AND REST TIMES MUST BE CONSIDERED. THIS ARTICLE PROVIDES COACHES AND PRACTITIONERS WITH A SHORT REVIEW OF LITERATURE ON THE EFFECT OF WBV ON VJ AND A GUIDE ON HOW TO IMPLEMENT AN ACUTE BOUT OF WBV BEFORE AN ACUTE BOUT OF VJ PERFORMANCE.

The influence of multiple sensory impairments on functional balance and difficulty with falls among U.S. adults.

OBJECTIVE Studies have looked at the individual associations of sensory impairment on balance, but no population-based studies have examined their combined association on balance and difficulty with falls. Thus, the purpose of this study was to examine both the independent associations and combined associations of visual impairment, peripheral neuropathy, and self-reported hearing loss with the odds of reporting difficulty with falls and functional balance. METHODS Data from the 2003-2004 National Health and Nutrition Examination Survey were used. Vision and peripheral neuropathy were objectively measured, and hearing was self-reported. Balance testing consisted of a modified Romberg test. After exclusions, 1662 (40-85years of age) participants provided complete data on the study variables. RESULTS Sensory impairment was associated with perceived difficulty of falls and functional balance. Participants who presented a single sensory impairment had 29% reduced odds of having functional balance (95% CI=0.54-0.93, p=0.01) and increased odds of reporting difficulty with falls by 61% (95% CI=0.99-2.60, p=0.05). Moreover, our multisensory models showed some evidence of a dose-response relationship, in that sensory impairment of multiple sensory systems was associated with worse balance (OR =0.59, CI=0.35-1.00, p=0.05) and perceived difficulty of falls (OR =5.02, 95% CI=1.99-12.66, p=0.002) when compared to those with less sensory impairment. CONCLUSION Multiple sensory impairment is associated with significantly higher odds of both reporting difficulty with falls and balance dysfunction, which may lead to a subsequent fall, ultimately compromising the individuals health.

Effects of whole body vibration on muscle contractile properties in exercise induced muscle damaged females

Determining muscle contractile properties following exercise is critical in understanding neuromuscular function. Following high intensity training, individuals often experience exercise induced muscle damage (EIMD). The purpose of this investigation was to determine the effect of whole-body vibration (WBV) on muscle contractile properties following EIMD. Twenty-seven females volunteered for 7 sessions and were randomly assigned to a treatment or control group. Muscle contractile properties were assessed via voluntary torque (VT), peak twitch torque (TT), time to reach peak torque, half relaxation time of twitch torque, percent activation (%ACT), rate of rise (RR), rate of decline (RD), mean and peak electromyography during maximum voluntary isometric contraction. Two testing sets were collected each day, consisting of pre measures followed by WBV or control and post measures. A mixed factor analysis of variance was conducted for each variable. %ACT measures found baseline being less than day 1 in both measures in the control group. TT was found to be greater in the control group compared to WBV group. TT and VT baseline measures were greater than all other time points. RR showed control group had higher values than WBV group. These results indicate that WBV following EIMD had some positive effects on muscle contractile properties.