The effects of cryotherapy versus cryostretching on clinical and functional outcomes in athletes with acute hamstring strain.

PURPOSE: Hamstring strain is a common sport injury that results in pain and functional limitation. Despite its high frequency in active populations, there is no agreement regarding the best method used for early intervention of hamstring strain. The aim of the present study was to compare the effects of cryotherapy and cryostretching on clinical and functional outcomes in athletes with acute hamstring strain. MATERIALS AND METHODS: Thirty seven elite athletes with an acute grade I or II hamstring strain were randomly assigned to either cryotherapy (n = 19) or cryostretching (n = 18) group, receiving 5 sessions of supervised treatment plus home-based intervention monitored by the therapist. Pre-treatment to post-treatment changes in pain, active and passive knee extension range of motion and functional status were compared between the two groups. RESULTS: Compared to cryotherapy, cryostretching resulted in larger improvement of function and passive knee extension range of motion. Changes in active knee extension range of motion and pain severity were not significantly different between the two groups. CONCLUSION: A rehabilitation protocol involving gentle stretching following cryotherapy is more effective than cryotherapy alone in the improvement of function and passive knee range of motion in patients with grade I and II hamstring strain.

Effect of dual-tasking on dynamic postural control in individuals with and without nonspecific low back pain.

OBJECTIVE: The purpose of this study was to compare the effect of dual tasking on postural and cognitive performance between participants with and without nonspecific chronic low back pain. METHODS: In this 3-factor mixed-design study, dynamic postural stability was assessed in 15 patients with chronic nonspecific low back pain and 15 age-, sex-, and size-matched asymptomatic participants. Bilateral stance on a Biodex Balance System was investigated at 3 levels of postural task difficulty (different platform stabilities levels with eyes open and closed) and 2 levels of cognitive task difficulty (with or without auditory Stroop test). We measured anterior-posterior, medial-lateral, and overall indices for postural performance. Average reaction time and error ratio of a modified auditory Stroop test were calculated as measures of the cognitive task performance. RESULTS: Mixed-design 3-way analyses of variance revealed significant interactions. Post hoc 2-way analyses of variance showed significant group by cognitive task difficulty for anterior-posterior (P < .001), medial-lateral (P = .003), and overall stability indices (P < .001) on a stiffness level of 5 with eyes closed. At this level, there were significant differences between single- and dual-task conditions for anterior-posterior (P < .001), medial-lateral (P = .02), and overall stability indices (P < .001) only in the chronic low back pain group. Also, at the most difficult postural conditions, participants with chronic low back pain increased their error ratio (P = .002), whereas matched asymptomatic individuals increased their reaction time (P < .01) of the auditory Stroop test. CONCLUSION: Postural task performance is attenuated by cognitive loading at a moderate level of postural task difficulty. Therefore, to observe the effect of attentional demands of postural control, task difficulty should be considered.

Intrasession and intersession reliability of postural control in participants with and without nonspecific low back pain using the Biodex Balance System.

OBJECTIVE: The purpose of this study was to evaluate the reliability of the Biodex Balance System (BBS) (Biodex Medical Systems, Shirley, NY) in chronic low back pain (CLBP) patients and healthy individuals in various conditions of postural and cognitive difficulty. METHODS: In this methodological study, using the BBS, dynamic balance of 15 CLBP patients and 15 healthy matched individuals was assessed during bilateral stance in combined conditions of visual feedback (eyes open and eyes closed) and platform stability (levels 5 and 3), either isolated or concurrent with performing cognitive task (auditory Stroop task). The Overall stability index, anterior-posterior stability index, and medial-lateral stability index, provided by BBS as measures of postural performance, were recorded. Intraclass correlation coefficient (ICC), standard error of measurement, and coefficient of variation were used to determine intersession and intrasession reliability of postural and cognitive measures. RESULTS: Biodex Balance System stability indices were more reliable in the CLBP (compared with healthy) group. The intersession ICCs in CLBP group for anterior-posterior stability index ranged from 0.60 to 0.88, for medial-lateral stability index from 0.64 to 0.94, and for OASI from 0.63 to 0.91. The intersession ICCs in healthy group for anterior-posterior stability index ranged from 0.42 to 0.86, for medial-lateral stability index from 0.56 to 0.89, and for OASI from 0.54 to 0.84. Biodex Balance System stability indices were more reliable in eyes-closed (compared with eyes-open) condition and platform stability level 5 (compared with level 3). CONCLUSION: Biodex Balance System stability indices appear to be reliable measures of postural control in the CLBP patients especially in more challenging conditions, such as when standing with eyes closed.

Effect of expertise in shooting and Taekwondo on bipedal and unipedal postural control isolated or concurrent with a reaction-time task.

It was hypothesized that training in 'static balance' or 'dynamic balance' sports has differential effects on postural control and its attention demands during quiet standing. In order to test this hypothesis, two groups of female athletes practicing shooting, as a 'static balance' sport, and Taekwondo, as a 'dynamic balance' sport, and a control group of non-physically active females voluntarily participated in this study. Postural control was assessed during bipedal and unipedal stance with and without performing a Go/No-go reaction time task. Visual and/or support surface conditions were manipulated in bipedal and unipedal stances in order to modify postural difficulty. Mixed model analysis of variance was used to determine the effects of dual tasking on postural and cognitive performance. Similar pattern of results were found in bipedal and unipedal stances, with Taekwondo practitioners displaying larger sway, shooters displaying lower sway and non-athletes displaying sway characteristics intermediate to Taekwondo and shooting athletes. Larger effect was found in bipedal stance. Single to dual-task comparison of postural control showed no significant effect of mental task on sway velocity in shooters, indicating less cognitive effort invested in balance control during bipedal stance. We suggest that expertise in shooting has a more pronounced effect on decreased sway in static balance conditions. Furthermore, shooters invest less attention in postures that are more specific to their training, i.e. bipedal stance.

Reliability of force-platform measures of postural sway and expertise-related differences.

CONTEXT: Although reliability is a population-specific property, few studies have investigated the measurement error associated with force-platform parameters in athletic populations. OBJECTIVE: To investigate the skill-related differences between athletes and nonathletes in reliability of center-of-pressure (COP) summary measures under eyes-open (EO) and eyes-closed (EC) conditions. DESIGN: Test-retest reliability study. SETTING: COP was recorded during double-leg quiet standing on a Kistler force platform before and after a fatiguing treadmill exercise, with EO and EC. PARTICIPANTS: 31 male participants including 15 athletes practiced in karate and 16 nonathletes. MAIN OUTCOME MEASURES: Standard deviation (SD) of amplitude, phase-plane portrait, SD of velocity, mean total velocity, and area were calculated from 30-s COP data. Intraclass correlation coefficient (ICC), standard error of measurement, and coefficient of variation (CV) were used as estimates of reliability and precision. RESULTS: Higher ICCs were found for COP measures in the athlete (compared with the nonathlete) group, postfatigued (compared with prefatigued) condition, and EC (compared with EO) tests. CVs smaller than 15% were obtained for most of the COP measures. SD of velocity in the anteroposterior direction showed the highest reliability in most conditions. CONCLUSIONS: Tests with EC and to a lesser extent tests performed in the athlete group and in the postfatigued condition showed better reliability.