Objective: To investigate if a single massage of the hamstring muscle group would alter the performance of the sit and reach test. Methods: Before treatment, each of 11 male subjects performed the sit and reach test. The treatment consisted of either massage of the hamstring muscle group (both legs, total time about 15 minutes) or supine rest with no massage. Performance of the sit and reach test was repeated after treatment. Each subject returned the subsequent week to perform the tests again, receiving the alternative treatment relative to their initial visit. Mean percentage changes in sit and reach scores after treatment were calculated for the massage and no massage treatments, and analysed using Student's t tests. Results: Mean (SD) percentage changes in sit and reach scores after massage and no massage were small (6.0 (4.3)% and 4.6 (4.8)% respectively) and not significantly different for subjects with relatively high (15 cm and above) values before treatment. Mean percentage changes in sit and reach scores for subjects with relatively low values before treatment (below 15 cm) were large (18.2 (8.2)% and 15.5 (16.2)% respectively), but no significant differences were found between the massage and no massage groups. Conclusions: A single massage of the hamstring muscle group was not associated with any significant increase in sit and reach performance immediately after treatment in physically active young men. F lexibility describes the range of motion of a joint. Enhanced flexibility is desirable in locomotor (synovial) joints for a number of reasons. These include increased reach or stride length, and thus, during a repeated activity over a fixed distance/displacement, potentially smaller number of contraction cycles. Activation and deactivation of muscle consumes energy over and above force production, and therefore the fewer times muscle is turned on and off, the less energy is consumed. Equally, greater range of motion effectively means a longer time frame over which muscle contraction can take place. When muscles are allowed sufficient time to accelerate and decelerate limb segments, connective tissues are spared and are therefore less prone to rupture. Thus enhanced flexibility is associated with improved movement economy and reduced risk of injury.
Traditionally, leg cycle ergometry is used to assess the power output of the lower limbs. However, it is suspected that the upper body makes a significant, albeit as yet unknown, contribution to the measured power output, and as such, the lean mass of the whole body should be considered during ergometric assessment. To test this idea, indices of mechanical power output were obtained from 11 subjects during high intensity leg cycle ergometry tests (20 second duration; 75 grams per kilogram total body mass) using two protocols: one with a standard handle-bar grip (with grip) and one with supinated wrists (without-grip). Peak mechanical power, mean mechanical power, fatigue index and total mechanical work values were calculated for each subject during each test and the sample mean differences associated with the two protocols were compared using paired Student t-tests. The with-grip protocol yielded significantly greater peak mechanical power output than the without-grip protocol (886+/-124 W and 815+/-151 W, respectively), suggesting a significant upper body contribution to the maximum power output measured for the legs. As a first step towards quantifying the upper body involvement during leg cycle ergometry, surface electromyography of the forearm musculature was measured in a twelfth subject whilst performing each of the test protocols. During the with-grip ergometer tests, the intensity of electrical activity in the forearm musculature was similar, if not greater than, the intensity of electrical activity recorded for the forearm musculature during 100% maximum voluntary hand grip-dynamometer contractions, suggesting maximum isometric-type forearm muscle contraction during the with-grip leg ergometry tests. These findings suggest that the performance of traditional-style leg cycle ergometry requires a muscular contribution from the whole body. As such, researchers should be mindful of this, both in terms of the allocation of ergometer loads, and in the analysis of blood-borne metabolites.
Four-point bending was used to apply pure extension and flexion moments to the ligamentous lumbosacral spine and pelvic girdle of monkey (Macaca fascicularis), rabbit (domestic and wild, Oryctolagus cuniculus), badger (Meles meles), wallaby (Wallabia rufogrisea frutica), sheep (Ovis aries), seal (Phoca vitulina) and tiger (Panthera tigris). The absolute ranges of angular change in lumbar-lumbar joints (from X-radiographs) were considerable and similar in monkey and wallaby (greater in flexion) and in rabbit and badger (symmetrical in extension and flexion). Mass-specific bending comparisons showed that monkey and seal joints were the most and least resistant, respectively, to these moments. The patterns of mobility showed no clear scaling effects. Subsequently, additional ligamentous joint complexes (three vertebrae and two intervertebral discs) of monkey, wallaby, tiger, jaguar (Panthera onca) and seal (Halichoerus grypus) were subjected to cyclic extension and flexion moments. Changes in intervertebral angle (y, from X-radiographs) were modelled as functions of applied specific bending moments (x):y=A(1-e-Bx). A and B values represented bending capacities and joint compliances respectively. Homologous monkey and wallaby joints had considerable flexion capacities, with low compliances. Homologous jaguar and tiger joints had limited flexion capacities, but greater compliances. The data suggest that flexion resistance may be controlled by different mechanisms in different species.
The aim of this study was to investigate whether a single massage of the hamstring muscles would alter selected electromyographic characteristics of biceps femoris during a sub-maximal isometric contraction. Eleven healthy young males participated in this crossover study. They were randomly assigned to two groups, receiving either a 15-minute hamstring muscle massage or a 15-minute prone rest. One week later they returned to receive the alternate intervention. Immediately pre- and post-intervention, participants were instructed to contract their muscles just sufficiently to maintain right knee flexion (5 degrees from full extension) for 30 seconds. Simultaneous to this contraction, surface electromyography (EMG) was used to record the electrical activity of right biceps femoris. Electromyograms were analyzed by calculating the averaged/integrated EMG (aEMG) and median frequency (MF) for each of 14 one-second windows, sampled every two seconds throughout the 30-second contractions per participant. Mean values of aEMG and MF were calculated per participant (aEMGmean and MFmean), pre- and post-massage or rest intervention. Group means (n = 11) of aEMGmean and MFmean were then calculated and compared using a repeated measures analysis of variance (ANOVA) procedure (p < 0.05). Rates of change of aEMG and MF throughout each 30-second contraction were represented by their respective gradients as functions of time. These gradients were similarly compared pre- to post-intervention using repeated measures ANOVA (p < 0.05). For the young healthy males considered in this study, a single massage of the hamstring muscles had no statistically significant effects on selected electromyographic characteristics of biceps femoris during sub-maximal isometric contractions (p > 0.05).
Three-point cyclic bending was applied to intervertebral joint complexes (three vertebrae with two intervertebral discs) of monkey (Macaca fascicularis), wallaby (Wallabia rufogrisea frutica), tiger (Panthera tigris), jaguar (Panthera onca) and seal (Halichoerus grypus). Force-displacement loops were recorded for intact specimens in both extension and flexion. Reductions in peak forces at given displacements were measured, following lesions of ventral ligaments, superspinous ligaments, interspinous ligaments and muscles, ligamenta flava and the articular capsules. Subsequently, the vertebral arches were removed from the specimens to test the bending resistance of the intervertebral discs alone. The results of these lesion experiments, coupled with details of intervertebral joint anatomy, suggest that extension resistance is ultimately due to articular joint impaction for all species tested. The prominent ligamenta flava of the monkey and wallaby contrast with the robust discs of jaguar and tiger and illustrate two distinct mechanisms for resisting flexion in mammalian intervertebral joints. The conspicuous absence of soft structural elements in seal intervertebral joints contributes to their low bending resistance. The implications of these findings for mammalian locomotion, behaviour and scaling are discussed.
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