Cui Zhang, Qipeng Song, Wei Sun and Yu Liu
Daily stair activities have become increasingly challenging for older adults with deterioration in physical and cognitive capabilities. However, the dynamic stability of older adults during stair descent under a concurrent dual-task condition remains undetermined. The gait and dynamic stability variables of 40 healthy older adults were measured under single- and dual-task conditions during stair descent. The step length, step width, and single support time did not significantly increase (p > .05) under the dual-task condition during stair descent. The medial–lateral center of mass velocity significantly increased (p < .003), whereas the medial–lateral margin of dynamic stability value significantly decreased (p < .006) at the landing and initial single support under the dual-task condition during stair descent. The self-regulatory ability of healthy older adults under the dual-task condition during stair descent was underestimated. Dual tasking displayed a positive impact on the anterior–posterior dynamic stability of healthy older adults.
Andrea Biscarini, Samuele Contemori and Giuditta Grolla
Context: Previous studies highlighted that exercises executed on unstable surfaces can yield important benefits to the function of the core musculature in rehabilitation settings, general conditioning settings, and athletic training when properly introduced within a periodized training schedule. No previous study has analyzed core-stability exercises executed in lying, quadruped, plank, and bridge positions on a whole-body wobble board (WWB) specifically designed to accommodate the exerciser’s entire body and promote whole-body instability. We have designed a WWB allowed to roll in a plane perpendicular to its longitudinal axis to promote proactive and reactive activation of the core muscles with a transverse or diagonal line of action, which provides trunk and pelvic stability with low spine compression forces. Purpose: To determine the effect of the use of this newly designed WWB by assessing differences in core-muscle activity during core-stability exercises performed on the ground, in a stable condition, and on the WWB. Design: Controlled laboratory study. Setting: Research laboratory. Patients or Other Participants: Eighteen participants recruited from fitness centers. Intervention(s): The electromyographic (EMG) activity of lumbopelvic and scapular muscles has been recorded during core-stability exercises executed on the WWB (unstable condition) and on ground (stable condition). Main Outcome Measure(s): Mean and peak EMG activity were compared between stable and unstable condition with paired t tests or Wilcoxon signed-rank tests. Results: Overall, exercises performed on the WWB yielded significantly higher EMG activity in the serratus anterior and anterolateral abdominal muscles compared with the same exercises executed on the ground. Conversely, for the bird dog exercise, lower-back muscle activity was significantly higher on the ground. Conclusions: Compared with the ground, core-stability exercises executed on WWB constitute a simple and effective strategy to increase the activity level of the core muscles that control transverse-plane lumbopelvic and trunk stability, avoiding the use of external overload.
Ufuk Ersoy, Umut Ziya Kocak, Ezgi Unuvar and Bayram Unver
Context: Mobilization has been used for enhancing muscle strength. Objective: The aim of this study was to investigate the acute effect of talocrural joint mobilization on ankle dorsiflexor muscle strength in healthy individuals, which has not yet been studied. Design: Randomized controlled single-blind study. Setting: University laboratory. Participants: Forty-eight healthy individuals. Interventions: Maitland grade III (study group) versus Maitland grade I (control group) mobilizations. Main Outcome Measures: Muscle strength measurements were performed using a handheld dynamometer at baseline, immediately after the mobilization, and 30 minutes after mobilization. Results: At baseline, the physical characteristics and muscular strength were similar in both groups (P > .05). According to Friedman analysis, a significant difference was detected following the mobilization in the study group (P < .001), and while the muscle strength at immediately after the mobilization and at 30 minutes after mobilization was significantly higher than baseline (P < .001), no significant differences were observed between 30 minutes after mobilization and immediately after the mobilization (P = .17). However, no significant changes were detected in the control group. The study group was found superior to the control group in terms of muscle strength differences following the mobilization (P < .001). Conclusion: The ankle dorsiflexor muscle strength might be increased by performing Maitland grade III mobilization, and this increase might be preserved for 30 minutes, while Maitland grade I mobilization did not lead to such an improvement in healthy individuals.
Chad Van Ramshorst and Woochol Joseph Choi
This study investigated the contact forces and muscle activation during 2 choreographed fall techniques in contemporary dancers and how these were affected by the fall technique. Ten collegiate-level dancers were instructed in 2 choreographed falls: (1) an anteriorly focused fall involving ankle plantar flexion, knee flexion, and hip flexion with dispersion of forces up the anterior surface of the shank (technique 1) and (2) a laterally focused fall involving inversion at the ankle with dispersion of forces up the lateral aspect of the shank (technique 2). The knee and hip contact forces were 26.3% smaller (technique 1: 1743 N vs technique 2: 1284 N) and 24.1% greater (technique 1: 1334 N vs technique 2: 1656 N), respectively, in technique 2 (P < .03). At the time of knee contact, percentage of maximal voluntary isometric contraction (%MVIC) was 45.8% greater for rectus femoris muscle (technique 1: 7.2% vs technique 2: 10.5%) and 96.9% greater for gluteus medius muscle (technique 1: 3.2% vs technique 2: 6.3%) (P < .01) in technique 2. The results provide insight into determining safer landing strategies to avoid knee injuries in individuals who experience a fall (ie, dancers, athletes, and older adults).
Hannah Horris, Barton E. Anderson, R. Curtis Bay and Kellie C. Huxel Bliven
Context: Altered diaphragm function is linked to decreased core stabilization, postural changes, and decreased function. Two clinical tests used to assess breathing are the Hi-lo and lateral rib expansion (LRE) tests. It is currently unknown how breathing classification based on these tests differ and how their results are affected by varying test positions. Objective: To compare the results of breathing tests when conducted in varying test positions. Design: Prospective cross-sectional study. Setting: University laboratory. Participants: A total of 50 healthy adults (females 31 and males 29; age 29.3 [4.1] y; height 170.0 [10.4] cm; weight70.7 [15.1] kg). Intervention(s): Hi-lo and LRE tests in supine, seated, standing, and half-kneeling body positions. All tests were recorded and later scored by a single examiner. A generalized estimating equations approach with breathing test and body position as factors was used for analysis. Pairwise comparison with Bonferroni correction was used to adjust for multiple tests. Statistical significance was set at P = .05, 2 tailed. Main Outcome Measures: Hi-lo and LRE tests were scored based on the presence or absence of abdominal excursion, LRE, and superior rib cage migration. Following scoring, results were classified as functional or dysfunctional based on observation of these criteria. Results: A significant breathing test × test position interaction (P < .01) was noted, as well as main effects for test (P < .01) and test position (P < .01). All Hi-lo test positions identified significantly more dysfunctional breathers in positions of increased stability demand (P < .01), except between standing and half-kneeling positions (P = .52). In the LRE test, all positions were similar (P > .99) except for half-kneeling, which was significantly different from all other positions (P < .01). Conclusions: The Hi-lo test and LRE tests assess different breathing mechanics. Clinicians should use these tests in combination to gain a comprehensive understanding of a person’s breathing pattern. The Hi-lo test should be administered in multiple testing positions.
Roel De Ridder, Julien Lebleu, Tine Willems, Cedric De Blaiser, Christine Detrembleur and Philip Roosen
Context: Wearable sensor devices have notable advantages, such as cost-effectiveness, easy to use, and real-time feedback. Wirelessness ensures full-body motion, which is required during movement in a challenging environment such as during sports. Research on the reliability and validity of commercially available systems, however, is indispensable. Objective: To confirm the test–retest reliability and concurrent validity of a commercially available body-worn sensor—BTS G-WALK® sensor system—for spatiotemporal gait parameters with the GAITRite® walkway system as golden standard. Design: Reliability and concurrent validity study. Setting: Laboratory setting. Participants: Thirty healthy subjects. Main Outcome Measures: Spatiotemporal parameters: speed, cadence, stride length, stride duration, stance duration, swing duration, double support, and single support. Results: In terms of test–retest reliability of the BTS G-WALK® sensor system, intraclass correlation coefficient values for both the spatial and temporal parameters were excellent between consecutive measurements on the same day with intraclass correlation coefficient values ranging from .85 to .99. In terms of validity, intraclass correlation coefficient values between measurement systems showed excellent levels of agreement for speed, cadence, stride length, and stride duration (range = .88–.97), and showed poor to moderate levels of agreement (range = .12–.47) for single/double support and swing/stance duration. Bland–Altman plots showed overall percentage bias values equal to or smaller than 3% with limits of agreement ≤15% (speed, cadence, stride length, stride duration, swing duration, and stance duration). Only for single and double support, the limits of agreement were higher with, respectively, −15.4% to 19.5% and −48.0% to 51.4%. Conclusion: The BTS G-WALK® sensor system is reliable for all measured spatiotemporal parameters. In terms of validity, excellent concurrent validity was shown for speed, cadence, stride length, and stride duration. Cautious interpretation is necessary for temporal parameters based on final foot contact (stance, swing, and single/double support time).
Benjamin S. Killen, Krista L. Zelizney and Xin Ye
Context: Static stretching (SS) and self-administered foam rolling (SAFR) are both effective techniques often used in rehabilitation settings to improve one’s range of motion (ROM). However, their effects on nonintervened contralateral limb’s performance remain equivocal. Objective: To examine the acute effects of unilateral hamstring’s SS and SAFR on the contralateral hip-flexion passive ROM and the strength performance. Design: Randomized crossover trial. Setting: Controlled laboratory. Participants: A total of 23 healthy young adults (13 males and 10 females) participated in this investigation. Interventions: Ten sets of 30-second SS or SAFR were performed on the participants’ dominant hamstring muscles. Main Outcome Measures: Before (pre) and after (post) the interventions, the contralateral hip-flexion passive ROM, the isometric strength of the contralateral hamstrings, and surface electromyography amplitude were measured. Separate 2-way (time × intervention) repeated measures analyses of variance were used to examine the changes in the dependent variables. Results: Both interventions significantly increased the contralateral hip-flexion passive ROM. In addition, the post-ROM value was significantly greater (P = .03) for the SS (mean ± SE = 73.5° ± 4.7°) than that for the SAFR (mean ± SE = 70.3° ± 4.5°). There were also main effects for time (P = .03) and intervention (P = .02) for the contralateral hamstring strength. However, no significant interaction or main effects were found for the normalized electromyography amplitude of the knee flexor muscles. Conclusions: The increased contralateral hip-flexion passive ROM following both interventions was likely due to the enhanced stretch tolerance. However, the differential strength performance responses might be due to different neural mechanisms, which are proposed and discussed.
Pablo Fanlo-Mazas, Elena Bueno-Gracia, Alazne Ruiz de Escudero-Zapico, José Miguel Tricás-Moreno and María Orosia Lucha-López
Context: Tightness or lack of flexibility of several muscles of the thigh has been associated with patellofemoral joint pain. A tight iliotibial band can lead to laterally located patella and an abnormal patellar tracking pattern. Diacutaneous fibrolysis (DF) is commonly used to reduce muscle tightness, but no studies have evaluated the effects of this technique in the treatment of patients with patellofemoral pain syndrome. Objective: To assess the effect of DF on patellar position in patients with patellofemoral pain syndrome. Design: A single-group, pretest–posttest clinical trial. Setting: University of Zaragoza. Participants: A total of 46 subjects with patellofemoral pain (20 males, 26 females; age: 27.8 [6.9] y). Intervention: Three sessions of DF. Main Outcome Measures: Patellar position measurement using real-time ultrasound scanning; pain intensity measured with visual analog scale and function measured with the Anterior Knee Pain Scale. Results: The application of 3 sessions of DF significantly increased the patellar position at posttreatment evaluation (P < .001) and at 1-week follow-up (P < .001). There was not a significant difference on patellar position between posttreatment and follow-up measurements (P = .28). There were also a statistically significant decrease in pain and increase in function at posttreatment and at 1-week follow-up measurements (P < .001). Conclusion: This study found that patellar position, pain intensity, and function were significantly improved after 3 sessions of DF and at 1-week follow-up.
Xiao Bao, Jie-Wen Tan, Ying Long, Howe Liu and Hui-Yu Liu
Objective: To study the effect of intermittent hypoxia training (IHT) for dizziness. Design: A single-blind, randomized controlled trial. All participants were recruited from a rehabilitation department in an acute university-affiliated hospital. Intervention: Participants with dizziness were randomly assigned to 2 groups (IHT group and control group). The Dizziness Handicap Inventory, Activities-specific Balance Confidence Scale, and Vertigo Visual Analog Scale were conducted at baseline, end of the fourth week. Results: Among 52 subjects, there were18 males and 34 females, ages 35 to 62 years old (mean [SD] = 46.9 [7.93]). Time length since onset ranged from 12 to 34 months (20.2 [7.15] mo). Dizziness Handicap Inventory, Activities-specific Balance Confidence Scale, Vertigo Visual Analog Scale scores, and attack frequencies of dizziness were improved after IHT intervention in the end of the fourth week. There were significant differences between the IHT group and the control group in the Dizziness Handicap Inventory, Activities-specific Balance Confidence Scale, Vertigo Visual Analog Scale scores, and attack frequencies of dizziness at the end of the fourth week (P < .05). No adverse events occurred during the study. Conclusion: IHT could improve dizziness after intervention at the end of the fourth week. IHT could be the effective method for treating dizziness.