Heel-Raised Foot Posture Does Not Affect Trunk and Lower Extremity Biomechanics During a Barbell Back Squat in Recreational Weight lifters.

Lee, S-P, Gillis, CB, Ibarra, JJ, Oldroyd, DF, and Zane, RS. Heel-raised foot posture does not affect trunk and lower extremity biomechanics during a barbell back squat in recreational weight lifters. J Strength Cond Res 33(3): 606-614, 2019-It is claimed that weightlifting shoes with a raised heel may lead to a more upright trunk posture, and thus reduce the risk of back injuries during a barbell back squat. These proclaimed biomechanical effects have not been thoroughly investigated. The purpose of this study was to compare trunk and lower extremity biomechanics during barbell back squats in three foot postures. Fourteen recreational weight lifters (7 men and 7 women) between the ages of 18 and 50 years performed barbell back squats in three conditions (barefoot on a flat surface, barefoot on a heel-raised platform, and wearing heel-raised weightlifting shoes) at 80% of their 1 repetition maximum. Surface electromyography was used to assess the activation of the knee extensors and paraspinal muscles at L3 and T12 spinal levels. A 3D motion capture system and an electrogoniometer recorded the kinematics of the thoracic spine, lumbar spine, and knee during the back squat to a depth where the hip was at least at the same level to the knee. Results indicated that none of the heel-raised foot postures significantly affected trunk and lower extremity muscle activation (thoracolumbar paraspinal [p = 0.52], lumbar paraspinal [p = 0.179], knee extensor [p = 0.507]) or the trunk angles (thoracolumbar spine [p = 0.348], lumbar spine [p = 0.283]) during the squat. Our results demonstrated that during barbell back squats, heel-raised foot postures do not significantly affect spinal and knee extensor muscle activations, and trunk and knee kinematics. Heel-raised weightlifting shoes are unlikely to provide significant protection against back injuries for recreational weight lifters during the barbell back squat.

The effect of modified jazz dance on balance, cognition, and mood in older adults.

PURPOSE: The purpose of this pilot study was to evaluate the impact of jazz dance class instruction on balance, cognition, and mood (specifically depression) in 13 healthy, community-dwelling, English-speaking older women with a mean age of 68. DATA SOURCES: Data were collected using self-report questionnaires (Folstein Mini Mental Status Examination [MMSE] and Geriatric Depression Scale [GDS]), and the sensory organization test (SOT) for balance measurements (using the NeuroCom Smart Balance Master) was performed at three time periods in the study: time 1: between week 1 and week 2 of jazz class (baseline), time 2: between week 8 and week 9 of jazz class (midpoint), and time 3: after week 15 of jazz class (final measurement). CONCLUSIONS: Differences in mean MMSE and GDS scores over time were not significant; however, SOT scores showed an increasing trend (p < .001). Data analysis using analysis of variance with repeated measures showed that balance measures improved throughout the duration of the study (F(2,10)= 19.68, p < .001). Post hoc analyses using paired t tests with a Bonferroni correction indicated that significant increases in balance occurred from time 1 to time 2 and from time 2 to time 3. These preliminary pilot study findings suggest that jazz dance does not impact cognition or mood but may improve balance in older women. This finding may have significant implications for fall prevention in the postmenopausal population. IMPLICATIONS FOR PRACTICE: Because falls are a leading cause of morbidity and mortality in older adults of both genders, research is needed to evaluate both the impact of jazz dance on balance in older men and jazz dance as a fall prevention strategy in aging adults. Additionally, longitudinal research with a larger sample size is needed to test the effectiveness of jazz dance as a strategy for improving balance, cognition, and mood.

The effect of a senior jazz dance class on static balance in healthy women over 50 years of age: a pilot study.

The purpose of this pilot study is to assess the impact of a senior jazz dance class on static balance for healthy women over 50 years of age using the NeuroCom Smart Balance Master System (Balance Master). A total of 12 healthy women aged 54-88 years completed a 15-week jazz dance class which they attended 1 time per week for 90 min per class. Balance data were collected using the Sensory Organization Test (SOT) at baseline (pre), at 7 weeks (mid), and after 15 weeks (post). An equilibrium score measuring postural sway was calculated for each of six different conditions. The composite equilibrium score (all six conditions integrated to 1 score) was used as an overall measure of balance. Repeated measures analyses of variance (ANOVAs) were used to compare the means of each participant's SOT composite equilibrium score in addition to the equilibrium score for each individual condition (1-6) across the 3 time points (pre, mid, post). There was a statistically significant difference among the means, p < .0005. Pairwise (Bonferroni) post hoc analyses revealed the following statistically significant findings for SOT composite equilibrium scores for the pre (67.33 + 10.43), mid (75.25 + 6.97), and post (79.00 + 4.97) measurements: premid (p = .008); prepost (p < .0005); midpost (p = .033). In addition, correlational statistics were used to determine any relationship between SOT scores and age. Results indicated that administration of a 15-week jazz dance class 1 time per week was beneficial in improving static balance as measured by the Balance Master SOT.