Harish Chander

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: 22.28u2009±u20092.2 years; height: 177.66u2009±u20096.9u2009cm; mass: 79.27u2009±u20097.6u2009kg) completed the study. Kinematic, kinetic and muscle activity variables were analyzed using a 3(footwear)u2009×u20094(gait trials) repeated-measures analysis of variance at pu2009=u20090.05. 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.

External load training does not alter balance performance in well-trained women

Abstract This study investigated the influence of external load training (ELT) on static and dynamic balance. Nineteen females stratified into two groups (ELT = 9, control = 10) completed three testing sessions over 6 weeks. The ELT group wore weighted vests (WV) of ~8% body mass for 32 h/week during daily living and three training sessions/week for 3 weeks. Following completion of ELT, a 3 week detraining (DET) phase was completed. Bilateral and unilateral static balance were assessed with eyes open and closed. Dynamic balance was assessed using the star excursion balance test (SEBT). Static and dynamic balance variables were analysed using a 2 (group) x 3 (time) between participants repeated measures ANOVA (p < 0.05). Results revealed significant reductions in average centre of pressure (COP) velocity in the control group on the non-dominant limb with eyes closed, and significantly greater reach distances in the ELT group on the SEBT for the posteromedial and medial directions on the dominant limb (p < 0.05). These findings suggest the ELT group did not significantly improve their balance in comparison to the control group. However, future research should further examine this unique, supplemental training method and the impact on balance performance.

Impact of occupational footwear during simulated workloads on energy expenditure

Limited research exists on the physiological demands of occupational footwear. Therefore, the purpose of this investigation was to examine the impact of tactical boots (TB) (0.5 kg) and steel-toed work boots (WB) (0.9 kg) on oxygen consumption (V̇O2) and cardiorespiratory responses during simulated walking protocols. Seventeen healthy male (age: 21.9 ± 2.0 years; height: 177.6 ± 4.8 cm; mass: 80.0 ± 9.4 kg) participants completed a total of four 20-min experimental walking trials: (1) WB horizontal protocol, (2) WB graded protocol, (3) TB horizontal protocol, and (4) TB graded protocol, following a randomized repeated measures design. On average, across each protocol, the larger mass of the WB increased absolute V̇O2 by 6.2% and 7.1% for the horizontal and graded protocols, respectively. The WB also caused a significant increase in absolute V̇O2 compared to TB during the horizontal protocol while walking at speeds of 4.0, 5.2, and 6.4 km/h (p < 0.05). No significant differences were observed for heart rate, breathing rate, or ratings of perceived exertion (p > 0.05). The results of this study indicate that wearing occupational footwear with a larger mass can significantly increase energy expenditure compared to footwear of lighter mass. However, energy expenditure increased without changes in physiological measures of energy expenditure. Footwear manufacturers may want to improve footwear design characteristics to maintain required safety guidelines while minimizing footwear mass.

Preliminary Analysis of StrongArm® Ergoskeleton on Knee and Hip Kinematics and User Comfort

This study was constructed to assess the influence of wearing semi-soft exoskeletons on hip and knee kinematics when engaging in a box lifting task. Six healthy college aged students (age: 21.7 ± 2.3; gender: 4 males, 2 females; height: 177.0 ± 3.4 cm; weight: 77.1 ± 17.9 kg; hand dominance: all right) completed box lifting tasks (at 10% and 20% of their body weight) while wearing no exoskeleton and two exoskeleton designs. Lifting a box at 20% body weight increased perceived exertion and was associated with poor hip and knee kinematics in some conditions. Wearing the StrongArm® V22 ERGOSKELETON without hand cables may diminish some of the poor kinematics associated with lifting objects.