Current Issue : October - December Volume : 2014 Issue Number : 4 Articles : 7 Articles
The effects of cooling on neuromuscular function and performance during gait are not fully examined.The purpose of this study\nwas to investigate the effects of local cooling for 20 min in cold water at 10?C in a climate chamber also at 10?C onmaximal isometric\nforce and electromyographic (EMG) activity of the lower legmuscles. Gait ground reaction forces (GRFs)were also assessed. Sixteen\nhealthy university students participated in the within subject design experimental study. Isometric forces of the tibialis anterior (TA)\nand the gastrocnemius medialis (GM) were measured using a handheld dynamometer and the EMG was recorded using surface\nelectrodes. Ground reaction forces during gait and the required coefficient of friction (RCOF) were recorded using a force plate.\nThere was a significantly reduced isometric maximum force in the TA muscle (P < 0.001) after cooling. The mean EMG amplitude\nof GM muscle was increased after cooling (P < 0.003), indicating that fatigue was induced.We found no significant changes in the\ngait GRFs and RCOF on dry and level surface.These findings may indicate that local moderate cooling 20 min of 10?C cold water,\nmay influence maximal muscle performance without affecting activities at sub-maximal effort....
Background. Hamstring injuries continue to affect active individuals and although inadequate muscle extensibility remains a\ncommonly accepted factor, little is known about the most effective method to improve flexibility. Purpose. To determine if an\nisolated neurodynamic sciatic sliding technique would improve hamstring flexibility to a greater degree than stretching or a placebo\nintervention in asymptomatic subjects with short hamstring syndrome (SHS). StudyDesign.Randomized double-blinded controlled\ntrial. Methods. One hundred and twenty subjects with SHS were randomized to 1 of 3 groups: neurodynamic sliding, hamstring\nstretching, and placebo control. Each subjectââ?¬â?¢s dominant leg was measured for straight leg raise (SLR) range ofmotion (ROM) before\nand after interventions. Data were analyzed with a 3 Ã?â?? 2 mixed model ANOVA followed by simple main effects analyses. Results.\nAt the end of the study, more ROM was observed in the Neurodynamic and Stretching groups compared to the Control group and\nmore ROM in the Neurodynamic group compared to Stretching group. Conclusion. Findings suggest that a neurodynamic sliding\ntechnique will increase hamstring flexibility to a greater degree than static hamstring stretching in healthy subjects with SHS.\nClinical Relevance.The use of neurodynamic sliding techniques to improve hamstring flexibility in sports may lead to a decreased\nincidence in injuries; however, this needs to be formally tested....
Background: Lateral humeral epicondylitis, or ââ?¬Ë?tennis elbowââ?¬â?¢, is a common condition with a variety of treatment\noptions. Platelet-rich plasma (PRP) and Autologous Whole Blood (AWB) represent new therapeutic options for\nchronic tendinopathies including tennis elbow. The aim of the present study was to compare the long term effects\nof PRP versus autologous whole blood local injection in patients with chronic tennis elbow.\nMethods: Seventy six patients with chronic lateral humeral epicondylitis with duration of symptoms more than\n3 months were included in this study and randomized into 2 groups. Group 1 was treated with a single injection of\n2 mL of autologous leukocyte rich PRP (4.8 times of plasma) and group 2 with 2 mL of AWB. Tennis elbow strap,\nstretching and strengthening exercises were administered for both groups. Pain and functional improvements were\nassessed using visual analogue scale (VAS), Mayo score (modified Mayo Clinic performance index for the elbow)\nand pressure pain threshold (PPT) at 0, 4, 8 weeks and 6 and 12 months.\nResults: All pain variables including VAS, PPT and Mayo scores improved significantly in both groups at each follow\nup intervals compared to baseline. No statistically significant difference was noted between groups regarding pain,\nfunctional scores and treatment success rates in all follow up examinations (P >0/05).\nConclusion: PRP and autologous whole blood injections are both effective methods to treat chronic lateral epicondylitis\nand their efficacy persisted during long term follow up. PRP was not superior to AWB in long term follow up....
Background: We developed a single stretch injury model to create damage near the musculotendinous junction\n(MTJ) of the gastrocnemius muscle in mice. Our hypothesis was that magnitude of muscle injury could be\ncontrolled by stepped shortening of the Achilles tendon (AT) prior to a lengthening contraction. Increased\nshortening would result in a greater isometric torque deficit and morphological damage 24 hours post-injury.\nMethods: Sixteen mice were randomly assigned to sham or injury predicated on stepped increases in AT\nshortening. The AT was exposed and placed in a customized stainless steel roller-clamp system to achieve a specific\nlevel of shortening; 0 mm (resting length), 0.7 mm or 1.4 mm. Plantar flexors were stimulated to tetany with a\nneedle electrode and then actively lengthened at 450�°/sec from neutral to 75�° of dorsiflexion. Passive and isometric\ntorques were measured pre- and immediately post-injury. Isometric torque was measured again 24 h post-injury.\nPeak isokinetic torque was recorded during eccentric injury.\nResults: Injury resulted in decreased passive and immediate absolute isometric torque only when induced with AT\nshortening. The percentage of pre-injury isometric torque was significantly lower in the AT shortened groups\nimmediately and 24 h post-injury, but was unaffected by the level of shortening. Relative isometric torque deficits\nwere noted in the 0 mm group only 24 h post-injury. Peak isokinetic torque during injury was similar in all groups.\nHistological evaluation 24 h post-injury revealed increased morphological damage near the MTJ in the AT shortened\ngroups.\nConclusion: Single stretch with AT shortening created morphological damage near the MTJ and isometric torque\ndeficits immediately and 24 h post-injury, but the magnitude of damage could not be titrated with stepped\nincreases in AT shortening. This model provides an opportunity to utilize transgenic mice in order to elucidate\ninflammatory mediators that promote regeneration and inhibit fibrosis in order to optimize therapeutic interventions\nfor complete functional recovery....
The anaerobic threshold (AT) has been one of the most studied of all physiological variables. Many authors have\nproposed the use of several markers to determine the moment at with the AT is reached. The present work\ndiscusses the physiological responses made to exercise - the measurement of which indicates the point at which\nthe AT is reached - and how these responses might be controlled by the central nervous system. The detection of\nthe AT having been reached is a sign for the central nervous system (CNS) to respond via an increase in efferent\nactivity via the peripheral nervous system (PNS). An increase in CNS and PNS activities are related to changes in\nventilation, cardiovascular function, and gland and muscle function. The directing action of the central command\n(CC) allows for the coordination of the autonomous and motor systems, suggesting that the AT can be identified in\nthe many ways: changes in lactate, ventilation, plasma catecholamines, heart rate (HR), salivary amylase and muscular\nelectrical activity. This change in response could be indicative that the organism would face failure if the exercise load\ncontinued to increase. To avoid this, the CC manages the efferent signals that show the organism that it is running out\nof homeostatic potential....
The aim of this study was to examine the effect of acute Rhodiola rosea (R. rosea) ingestion on substrate utilisation, mood state,\nRPE, and exercise affect. Ten males (mean age �± S.D. = 26 �± 6 years) completed two 30-minute cycling trials at an intensity of 70%\nof V?O2 max following ingestion of either 3mg?kg?1 body mass of R. rosea or placebo using a double-blind, crossover design. During\nexercise, heart rate and RPE were recorded. Participants completed measures of mood state and exercise affect before and after\nexercise. Expired air samples were taken during exercise to determine substrate utilisation. Repeated measures analysis of variance\nindicated that RPE was significantly lower at 30 minutes into exercise versus placebo (P = 0.003). Perceptions of arousal (P = 0.05)\nand pleasure were significantly higher after exercise with R. rosea compared to placebo (P = 0.003).Mood state scores for vigor were\nalso higher in R. rosea condition compared to placebo (P = 0.008). There were no significant differences in energy expenditure,\ncarbohydrate, or fat oxidation between conditions (P > 0.05). Ingestion of R. rosea favourably influenced RPE and exercise affect\nwithout changes in energy expenditure or substrate utilization during 30-minute submaximal cycling performance....
Background: The purpose of this study was to describe professional soccer players� perceptions towards injuries,\nphysical recovery and the effect of surface related factors on injury resulting from soccer participation on 3rd\ngeneration artificial turf (FT) compared to natural grass (NG).\nMethods: Information was collected through a questionnaire that was completed by 99 professional soccer players\nfrom 6 teams competing in Major League Soccer (MLS) during the 2011 season.\nResults: The majority (93% and 95%) of the players reported that playing surface type and quality influenced the\nrisk of sustaining an injury. Players believed that playing and training on FT increased the risk of sustaining a\nnon-contact injury as opposed to a contact injury. The players identified three surface related risk factors on FT,\nwhich they related to injuries and greater recovery times: 1) Greater surface stiffness 2) Greater surface friction 3)\nLarger metabolic cost to playing on artificial grounds. Overall, 94% of the players chose FT as the surface most likely\nto increase the risk of sustaining an injury.\nConclusions: Players believe that the risk of injury differs according to surface type, and that FT is associated with\nan increased risk of non-contact injury. Future studies should be designed prospectively to systematically track the\nperceptions of groups of professional players training and competing on FT and NG....
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