Context: The authors hypothesized that in people with hip-related groin pain, less static ankle dorsiflexion could lead to compensatory hip adduction and contralateral pelvic drop during step-down. Ankle dorsiflexion may be a modifiable factor to improve ability in those with hip-related groin pain to decrease hip/pelvic motion during functional tasks and improve function. Objective: To determine whether smaller static ankle dorsiflexion angles were associated with altered ankle, hip, and pelvis kinematics during step-down in people with hip-related groin pain. Design: Cross-sectional Setting: Academic medical center. Patients : A total of 30 people with hip-related groin pain (12 males and 18 females; 28.7 [5.3] y) participated. Intervention: None. Main Outcome Measures: Weight-bearing static ankle dorsiflexion with knee flexed and knee extended were measured via digital inclinometer. Pelvis, hip, and ankle kinematics during forward step-down were measured via 3D motion capture. Static ankle dorsiflexion and kinematics were compared with bivariate correlations. Results: Smaller static ankle dorsiflexion angles were associated with smaller ankle dorsiflexion angles during the step-down for both the knee flexed and knee extended static measures. Among the total sample, smaller static ankle dorsiflexion angle with knee flexed was associated with greater anterior pelvic tilt and greater contralateral pelvic drop during the step-down. Among only those who did not require a lowered step for safety, smaller static ankle dorsiflexion angles with knee flexed and knee extended were associated with greater anterior pelvic tilt, greater contralateral pelvic drop, and greater hip flexion. Conclusions: Among those with hip-related groin pain, smaller static ankle dorsiflexion angles are associated with less ankle dorsiflexion motion and altered pelvis and hip kinematics during a step-down. Future research is needed to assess the effect of treating restricted ankle dorsiflexion on quality of motion and symptoms in patients with hip-related groin pain.
Stefanie N. Foster, Michael D. Harris, Mary K. Hastings, Michael J. Mueller, Gretchen B. Salsich, and Marcie Harris-Hayes
Alexandre H. Nowotny, Mariane Guizeline Calderon, Bruno Mazziotti O. Alves, Marcio R. de Oliveira, Rodrigo A. de Carvalho Andraus, Andreo F. Aguiar, Cesar F. Amorim, Guillaume Leonard, and Rubens A. da Silva
Context: Chronic low-back pain (CLBP) may be associated with changes in postural balance in athletes as poor postural control during sports practice. Objective: To compare the postural control of athletes with and without CLBP during 2 one-legged stance tasks and identify the center of pressure (COP) cutoff values to determine the main differences. Designed: A cross-sectional study. Setting: Laboratory of functional evaluation and human motor performance. Participants: A total of 56 male athletes, 28 with and 28 without CLBP (mean age = 26 y). Intervention: The one-legged stance with knee extension and with the knee at 30° flexion tasks were measured and analyzed on a force platform. The participants completed three 30-second trials (30 s of rest between each trial). Main Outcome Measures: The COP parameters: the area of COP, mean COP sway velocity in both the anteroposterior and mediolateral directions, and total COP displacement were computed, and a receiver operating characteristics curve analysis was applied to determine the group differences. Results: Athletes with CLBP had poorer postural control (P < .01) in both tasks. The 30° knee flexion reported more postural instability than the knee extension for all COP parameters (a large effect size d = 0.80).The knee extension cutoffs identified were >7.1 cm2 for the COP area, >2.6 cm/s for the COP sway velocity in the anterior-posterior direction, and >3.2 cm/s for the mediolateral direction. Whereas, the 30° knee flexion cutoffs were >10.9 cm2 for the COP area, >2.9 cm/s for the COP sway velocity in the anterior-posterior direction, and >4.1 cm/s for the mediolateral direction. Both measures showed enough sensitivity and specificity (ie, area under the curve = 0.88 in and 0.80, respectively) to discriminate both groups. Conclusions: The athletes with CLBP had poorer postural control than the healthy athletes and obtained specific cutoff scores from the COP values.
Itsuroh Shimizu, Hiroichi Miaki, Katsunori Mizuno, Nobuhide Azuma, Takao Nakagawa, and Toshiaki Yamazaki
Context: Lumbar instability can cause lumbar spondylolisthesis and chronic low-back pain in sports situation. Abdominal hollowing is commonly used in clinical practice to preferentially target the transversus abdominis (TrA) to stabilize the lumbar vertebrae; however, the contribution of muscle elasticity and lateral slide of the TrA to lumbar stability has not yet been clarified. Objective: To clarify the contribution of elasticity and lateral slide of the TrA to lumbar stability and to identify an effective exercise to stabilize the lumbar vertebrae. Design: Experimental study. Setting: Laboratory. Patients: A total of 29 healthy males participated in this study. Interventions: The participants performed hollowing during measurement of muscle elasticity of TrA and both knees extension from crook lying position for pelvic stability measurement. Main Outcome Measures: Lumbar stability, muscle elasticity change ratio, and lateral slide amount of TrA. Results: There was a significant correlation between elasticity of the TrA and lumbar stability; however, no relationship was observed between lateral slide and lumbar stability or elasticity of the TrA. Conclusion: Elasticity of the TrA and lumbar stability was significantly correlated; therefore, improving the tonicity of the TrA may stabilize the lumbar vertebrae in healthy individuals. Moreover, hollowing with maximum effort may be effective as training aimed to stabilize the lumbar vertebrae for physical dysfunction due to lumbar instability.
Daichi Tomita, Tadashi Suga, Hiromasa Ueno, Yuto Miyake, Takahiro Tanaka, Masafumi Terada, Mitsuo Otsuka, Akinori Nagano, and Tadao Isaka
This study examined the relationship between Achilles tendon (AT) length and 100-m sprint time in sprinters. The AT lengths at 3 different portions of the triceps surae muscle in 48 well-trained sprinters were measured using magnetic resonance imaging. The 3 AT lengths were calculated as the distance from the calcaneal tuberosity to the muscle–tendon junction of the soleus, gastrocnemius medialis, and gastrocnemius lateralis, respectively. The absolute 3 AT lengths did not correlate significantly with personal best 100-m sprint time (r = −.023 to .064, all Ps > .05). Furthermore, to minimize the differences in the leg length among participants, the 3 AT lengths were normalized to the shank length, and the relative 3 AT lengths did not correlate significantly with personal best 100-m sprint time (r = .023 to .102, all Ps > .05). Additionally, no significant correlations were observed between the absolute and relative (normalized to body mass) cross-sectional areas of the AT and personal best 100-m sprint time (r = .012 and .084, respectively, both Ps > .05). These findings suggest that the AT morphological variables, including the length, may not be related to superior 100-m sprint time in sprinters.
Justine J. Reel
Corey A. Pew, Sarah A. Roelker, Glenn K. Klute, and Richard R. Neptune
The coupling between the residual limb and the lower-limb prosthesis is not rigid. As a result, external loading produces movement between the prosthesis and residual limb that can lead to undesirable soft-tissue shear stresses. As these stresses are difficult to measure, limb loading is commonly used as a surrogate. However, the relationship between limb loading and the displacements responsible for those stresses remains unknown. To better understand the limb motion within the socket, an inverse kinematic analysis was performed to estimate the motion between the socket and tibia for 10 individuals with a transtibial amputation performing walking and turning activities at 3 different speeds. The authors estimated the rotational stiffness of the limb-socket body to quantify the limb properties when coupled with the socket and highlight how this approach could help inform prosthetic prescriptions. Results showed that peak transverse displacement had a significant, linear relationship with peak transverse loading. Stiffness of the limb-socket body varied significantly between individuals, activities (walking and turning), and speeds. These results suggest that transverse limb loading can serve as a surrogate for residual-limb shear stress and that the setup of a prosthesis could be individually tailored using standard motion capture and inverse kinematic analyses.
Svend Erik Mathiassen
Devin S. Kielur and Cameron J. Powden
Context: Impaired dorsiflexion range of motion (DFROM) has been established as a predictor of lower-extremity injury. Compression tissue flossing (CTF) may address tissue restrictions associated with impaired DFROM; however, a consensus is yet to support these effects. Objectives: To summarize the available literature regarding CTF on DFROM in physically active individuals. Evidence Acquisition: PubMed and EBSCOhost (CINAHL, MEDLINE, and SPORTDiscus) were searched from 1965 to July 2019 for related articles using combination terms related to CTF and DRFOM. Articles were included if they measured the immediate effects of CTF on DFROM. Methodological quality was assessed using the Physiotherapy Evidence Database scale. The level of evidence was assessed using the Strength of Recommendation Taxonomy. The magnitude of CTF effects from pre-CTF to post-CTF and compared with a control of range of motion activities only were examined using Hedges g effect sizes and 95% confidence intervals. Randomeffects meta-analysis was performed to synthesize DFROM changes. Evidence Synthesis: A total of 6 studies were included in the analysis. The average Physiotherapy Evidence Database score was 60% (range = 30%–80%) with 4 out of 6 studies considered high quality and 2 as low quality. Meta-analysis indicated no DFROM improvements for CTF compared with range of motion activities only (effect size = 0.124; 95% confidence interval, −0.137 to 0.384; P = .352) and moderate improvements from pre-CTF to post-CTF (effect size = 0.455; 95% confidence interval, 0.022 to 0.889; P = .040). Conclusions: There is grade B evidence to suggest CTF may have no effect on DFROM when compared with a control of range of motion activities only and results in moderate improvements from pre-CTF to post-CTF. This suggests that DFROM improvements were most likely due to exercises completed rather than the band application.
Robert J. Reyburn and Cameron J. Powden
Context: Ankle braces have been theorized to augment dynamic balance. Objectives: To complete a systematic review with meta-analysis of the available literature assessing the effect of ankle braces on dynamic balance in individuals with and without chronic ankle instability (CAI). Evidence Acquisition: Electronic databases (PubMed, MEDLINE, CINAHL, and SPORTDiscus) were searched from inception to October 2019 using combinations of keywords related to dynamic balance, ankle braces, Star Excursion Balance Test (SEBT), Y-Balance Test (YBT), and Time to Stabilization. Inclusion criteria required that studies examined the effects of ankle braces on dynamic balance. Studies were excluded if they evaluated other conditions besides CAI, did not access dynamic balance, or did not use an ankle brace. Methodological quality was assessed using the Physiotherapy Evidence Database scale. The level of evidence was assessed using the Strength of Recommendation Taxonomy. The magnitude of brace effects on dynamic balance was examined using Hedges g effect sizes (ESs) and 95% confidence intervals (CIs). Random-effects meta-analysis was performed to synthesize SEBT/YBT and Time to Stabilization data separately. Data Synthesis: Seven studies were included with a median Physiotherapy Evidence Database score of 60% (range 50%–60%), and 4 were classified as high quality. Overall meta-analysis indicated a weak to no effect of braces on SEBT/YBT (ES = 0.117; 95% CI, −0.080 to 0.433; P = .177) and Time to Stabilization (ES = −0.064; 95% CI, −0.211 to 0.083, P = .083). Subanalysis of SEBT/YBT measures indicated a weak negative effect in healthy participants (ES = −0.116; 95% CI, −0.209 to −0.022, P = .015) and a strong positive effect in individuals with CAI (ES = 0.777; 95% CI, 0.418 to 1.136; P < .001). Conclusion: The current literature supports a strong effect of ankle braces on the SEBT/YBT in those with CAI. However, little to no dynamic balance changes were noted in healthy participants. Future research should include consistent ankle brace types, pathologic populations, and the examination of dynamic balance changes contribution to injury risk reduction.