Journal Issue: Vol. 1, No. 1
Background: The back squat exercise is a common and essential clinical rehabilitation exercise. As a compound movement of the lower limbs the cues to optimal movement technique are complex and difficult to identify. The aim of this study was to determine the influence of lower limb segment lengths on the biomechanics of movement when performing the back squat exercise.
Methods: Using 3D kinematic analysis the 28 subjects (male n
16, female n = 12) performed four sets of eight squats. The four independent variables were: load – (i) body-weight with no external load, and (ii) body-weight plus 50% body-weight external load; and width of stance – (iii) narrow stance equal to ASIS width; and (iv) wide equal to twice ASIS width.
Findings: The total squat pattern was different for genders and limb length correlations showed that genders created movement patterns of the lower body in squatting, which may have resulted due to these limb length differences. Males typically lean more forward allowing their spine to create greater movement and depth during the squat. Females utilise the knees and sacrum to adjust for depth, achieve greater hip flexion, and remain upright during the squat. The frequent correlations for limb lengths with the knees in females suggest females utilise the knees as a strategy to maintain synchronisation of the squat.
Interpretation: Taller women typically achieved greater knee angles, and taller men achieved smaller hip angles. Males and females do create different movement strategies for the squat movement and coaches and trainers should allow for this in both teaching and cueing of the squat movement pattern.
Objectives: Acute static stretching has been scrutinized as being detrimental to physical performance when incorporated as a pre-activity warm-up. Alternatively, it has been reported elsewhere that dynamic performance related movements may be more appropriate as a warm-up. Very little research has been done on the effects of acute bouts of static or dynamic stretching on balance performance. Therefore, the purpose of our study was to examine the effects of acute bouts of static stretching and dynamic stretching on balance performance in older adults. Methods: Participants in this study included 10 males and 10 females, aged 66.1Â±8.1 (meanÂ±SD) all age 50 or older, who were participating in a regular physical activity program at the time of testing and had varying amounts of exposure to balance training. Each participant underwent a static stretch, dynamic stretch, and no stretch protocol followed by a balance assessment using the Fullerton Advanced Balance Scale (FABS). Results: Analysis of variance showed no significant differences (p > 0.05) in cumulative FABS scores between pre-exercise static stretching (34.0Â±2.9), dynamic stretching (34.1Â±2.6) and no-stretching groups (33.7Â±2.1). Additionally, Friedman Tests completed for each individual balance challenge revealed no significant differences (p > 0.05) in the individual scores. Conclusion: No differences in balance performance (as evidenced by FABS scores) were found between experimental treatments. These findings suggest that when designing exercise programs for older adults the sequencing of flexibility exercise prior to balance exercise will not compromise balance performance.
How the Instantaneous Net Drag-force Profile can Quantify Front-crawl and Backstroke Swimming Technique: A Practical Perspective
The aim of this research was to use instantaneous net drag-force profiles to understand front-crawl and backstroke swimming technique. Twenty-nine elite front-crawl and 19 elite backstroke swimmers (FINA point ranking 924.5 Â± 69.0) were recruited. From the net drag-force profile the Minimum and Maximum net force occurred during the insweep phase and during the upsweep phase of the front-crawl stroke, respectively. When swimming backstroke the minimum and maximum net drag-forces occurred during the pull phase and push stroke phases, respectively. When turning their head to breath the swimmers increased the net drag-force by 22%, which could be detrimental to swimming performance. When comparing the variables of swimming speed and the range of force fluctuations participants who exhibited smaller intra-stroke force changes produced faster swimming speeds. This practical knowledge can assist coach, sports scientist or exercise professional in providing stroke correction during swimming.
The aim of this review was to evaluate and compare physical activity levels and physical responses of group exercises and evaluate methods of measuring these classes. The popularity of modern group exercise classes is evident by the more than 3 million classes per week offered by Les Mills International and the 81% of fitness business in Australia that offer group fitness classes. While general dance style aerobics have been researched, limited insight has been made into modern group exercise classes, leaving a gap in the knowledge of best practices when prescribing the various styles and programs as a healthy activity and measuring classes to accurately reflect physiological benefits. The purpose of this article is to present an overview of documented research and where possible identify gaps in knowledge in order to make recommendations for further study. A literature search was conducted in ProQuest, PubMed, Google Scholar, current reports and documentation was also sought through Fitness Australia and Les Mills International. There is an extensive amount of literature available exploring the benefits of more established techniques such as yoga, Tai Chi, Pilates and even dance style aerobics. However, when these styles of exercise are combined, or modernised with new techniques or equipment, the scope of literature is limited. Research available is restricted by inconsistencies in the type of equipment used, participants fitness level, variation in class structure, and instructor delivery.
Water has a density 800 times greater than that of air. During water exercise, kinetic and kinematic aspects such as body motion, ground reaction force, joint moment and muscle activity change dramatically compared with the same exercise forms on land mostly due to buoyancy and water drag force. This review of literature mainly focused on walking and running in water exercise. Furthermore, this article discussed future necessary study and practical implications. When walking in water, the motion was slower and joint motion was roughly similar to walking on land. However, some characteristics such as ground reaction force, lower extremity joint moment and muscle activity were much different from walking on land. During running in water, the motion was slower and joint motion was different from running on land. Ground reaction force and muscle activity showed discriminative differences compared with running on land. This review shows that investigation of kinesiology of running and other exercise forms in water were limited especially with regards to determining gender differences, and impact on those people with a disability or injury. Research of this nature would provide a useful suggestion for water exercise instruction to both different genders and populations. Key aspects of exercise in the water environment includes reduced gravity stress and increased safety without fear of injury or fall, which would suit a wide range of people. Future research possibilities were also discussed with practical implication for water exercise.