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Roman P. Kuster, Daniel Baumgartner, Maria Hagströmer and Wilhelmus J.A. Grooten

Background: Sedentary behavior (SB) is associated with several chronic diseases and office workers especially are at increased risk. SB is defined by a sitting or reclined body posture with an energy expenditure of ≤1.5 metabolic equivalents. However, current objective methods to measure SB are not consistent with its definition. There is no consensus on which sensor placement and type should be used. Aim: To compare the accuracy of newly developed artificial intelligence models for 15 sensor placements in combination with four signal types (accelerometer only/plus gyroscope and/or magnetometer) to detect posture and physical in-/activity during desk-based activities. Method: Signal features for the model development were extracted from sensor raw data of 30 office workers performing 10 desk-based tasks, each lasting 5 min. Direct observation (posture) and indirect calorimetry (in-/activity) served as the reference criteria. The best classification model for each sensor was identified and compared among the sensor placements, both using Friedman and post hoc Wilcoxon tests (p ≤ .05). Results: Posture was most accurately measured with a lower body sensor, while in-/activity was most accurately measured with an upper body or waist sensor. The inclusion of additional signal types improved the posture classification for some placements, while the acceleration signal already contained the relevant signal information for the in-/activity classification. Overall, the thigh accelerometer most accurately classified desk-based SB. Conclusion: This study favors, in line with previous work, the measurement of SB with a thigh-worn accelerometer and adds the information that this sensor is also accurate in measuring physical in-/activity while sitting and standing.

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Patti Millar and Julie Stevens

Past research has demonstrated that human resource training often results in improved individual and organizational performances. Yet, the focus has been on whether or not training has an impact on performance, rather than the nature of that impact. The purpose of this study is to investigate the nature of training-related outcomes in the context of one training program within the Canadian national sport sector. Interviews were conducted with key representatives from 12 Canadian national sport organizations. Findings showed the manifestations of performance change that occur as a result of training, revealing a new way of thinking at the individual level, a new way of doing within group and organizational processes, and a new way of being across organizations. Three theoretical perspectives—interpretation, learning, and institutional—are used to frame the discussion of the findings. Implications for practice and future research are presented.

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Liana M. Tennant, Erika Nelson-Wong, Joshua Kuest, Gabriel Lawrence, Kristen Levesque, David Owens, Jeremy Prisby, Sarah Spivey, Stephanie R. Albin, Kristen Jagger, Jeff M. Barrett, James D. Wong and Jack P. Callaghan

Spinal stiffness and mobility assessments vary between clinical and research settings, potentially hindering the understanding and treatment of low back pain. A total of 71 healthy participants were evaluated using 2 clinical assessments (posteroanterior spring and passive intervertebral motion) and 2 quantitative measures: lumped mechanical stiffness of the lumbar spine and local tissue stiffness (lumbar erector spinae and supraspinous ligament) measured via myotonometry. The authors hypothesized that clinical, mechanical, and local tissue measures would be correlated, that clinical tests would not alter mechanical stiffness, and that males would demonstrate greater lumbar stiffness than females. Clinical, lumped mechanical, and tissue stiffness were not correlated; however, gradings from the posteroanterior spring and passive intervertebral motion tests were positively correlated with each other. Clinical assessments had no effect on lumped mechanical stiffness. The males had greater lumped mechanical and lumbar erector spinae stiffness compared with the females. The lack of correlation between clinical, tissue, and lumped mechanical measures of spinal stiffness indicates that the use of the term “stiffness” by clinicians may require reevaluation; clinicians should be confident that they are not altering mechanical stiffness of the spine through segmental mobility assessments; and greater resting lumbar erector stiffness in males suggests that sex should be considered in the assessment and treatment of the low back.

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Reza Heydari Armaki, Keramatollah Abbasnia and Alireza Motealleh

Objective: Patellofemoral pain (PFP) is the most commonly reported musculoskeletal overuse injury in active individuals, such as athletes, and is a multifactorial problem with no definite cause identified to date. Some studies have shown a relationship between impaired core and trunk sensorimotor control and knee disorders, especially PFP. The aim of this study was to evaluate trunk flexion proprioception by comparing the repositioning error between healthy athletes and athletes with PFP. Design: Cross-sectional case–control study. Setting: Rehabilitation sciences research center. Participants: Twenty healthy athletes and 20 athletes with PFP. Main Outcome Measures: To examine proprioception of trunk flexors, the absolute active and passive repositioning error at 30° and 60° trunk flexion were evaluated with isokinetic dynamometry. The results were compared between the two groups. Results: In the PFP group, the active trunk repositioning error at 30° flexion was significantly greater than in the healthy individuals (P < .001). The mean absolute active repositioning error at 30° flexion was 3.04° (1.37°) in the PFP group and 1.50° (0.70°) in the control group. There was no significant difference between groups in the active trunk repositioning error at 60° flexion (P = .066). The mean absolute active repositioning error at 60° flexion was 2.96° (1.26°) in the PFP group and 2.18° (0.99°) in the control group. The passive trunk repositioning error at 30° and 60° flexion was significantly greater in the PFP group (P = .013 and P = .004, respectively). The mean absolute passive repositioning error at 30° and 60° flexion in the PFP group was 2.94° (0.80°) and 3.13° (1.19°), respectively, and was 2.08° (1.08°) and 1.96° (0.71°), respectively, in the control group. The calculated eta-squared value showed that joint repositioning errors had large effect sizes (0.15–0.32). Conclusion: Trunk proprioception in the flexion direction may be impaired in patients with PFP. This finding suggests that trunk proprioception training may be important in rehabilitation for athletes with PFP.

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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.

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Diulian Muniz Medeiros, César Marchiori and Bruno Manfredini Baroni

Context: Nordic hamstring exercise (NHE) has been widely employed to prevent hamstring strain injuries. However, it is still not clear which adaptations are responsible for the NHE preventive effects. Objectives: The aim of this study was to investigate the effects of NHE on knee flexors eccentric strength and fascicle length. Evidence Acquisition: The search strategy included MEDLINE, PEDro, and Cochrane CENTRAL from inception to April 2020. Randomized clinical trials that have analyzed the effects of NHE training on hamstring eccentric strength and/or fascicle length were included. Evidence Synthesis: From the 1932 studies identified, 12 were included in the systematic review, and 9 studies presented suitable data for the meta-analysis. All studies demonstrated strength increments in response to NHE training (10%–15% and 16%–26% in tests performed on the isokinetic dynamometer and on the NHE device, respectively), as well as significant enhancement of biceps femoris long head fascicle length (12%–22%). Meta-analysis showed NHE training was effective to increase knee flexors eccentric strength assessed with both isokinetic tests (0.68; 95% confidence interval, 0.29 to 1.06) and NHE tests (1.11; 95% confidence interval, 0.62 to 1.61). NHE training was also effective to increase fascicle length (0.97; 95% confidence interval, 0.46 to 1.48). Conclusions: NHE training has the potential of increasing both knee flexors eccentric strength and biceps femoris long head fascicle length.

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Chee Vang and Alexander Niznik

Clinical Scenario: Patellar tendinopathy is a common musculoskeletal disorder affecting the lower-extremities and a difficult condition to manage for athletes that are in season. To facilitate improvement in function and to decrease pain, initial treatment for patellar tendinopathy is typically conservative. Traditional interventions may include eccentric training, cryotherapy, patellar counterforce straps, oral anti-inflammatories, injectable agents, phonophoresis, iontophoresis, orthotics, therapeutic ultrasound, and extracorporeal shockwave. In addition, recent literature suggests that implementing isometric and isotonic contractions may be effective in reducing patellar tendon pain. Focused Clinical Question: How effective are isometric contractions compared with isotonic contractions in reducing pain for in-season athletes with patellar tendinopathy? Summary of Key Findings: Implementation of isometric and isotonic exercises statistically reduced pain levels in the short term of 4 weeks for in-season athletes; however, isometric contractions provided statistically greater pain relief immediately for up to 45 minutes postintervention compared with isotonic contractions. Clinical Bottom Line: Current evidence supports the use of isometric and isotonic contractions to reduce pain for in-season athletes with patellar tendinopathy. Based on the reviewed literature, clinicians should consider utilizing heavy loaded isometrics or progressive heavy loaded isotonic exercises, which showed reduction in pain levels immediately after intervention and at 4-week follow-up for both intervention groups. Isometric contractions appear to provide greater pain relief immediately after intervention. Strength of Recommendation: There is Grade B evidence from 2 level 2 randomized controlled trials and 1 level 3 randomized crossover study supporting the use of isometric and isotonic contractions to reduce patellar tendon pain for in-season athletes.

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Behnam Gholami-Borujeni, Ali Yalfani and Leila Ahmadnezhad

This study was conducted to evaluate the effects of 8-week inspiratory muscle training on activity in the ankle muscles of athletes with chronic low-back pain. A randomized controlled trial involving 45 men and women with chronic low-back pain was carried out. Electromyography activity in the tibialis anterior, peroneus longus, gastrocnemius medialis, and gastrocnemius lateralis muscles of the dominant leg was recorded. Secondary outcomes included biopsychosocial indices, such as pain, disability, anxiety and depression, fear-avoidance beliefs, and fear of (re)injury. Static and dynamic overhead squat tests showed that inspiratory muscle training decreased activity in the tibialis anterior, peroneus longus, and gastrocnemius medialis muscles. In the static single-leg squat test and the descending phase of the dynamic equivalent, such a decrease was observed in all the 4 muscles. Inspiratory muscle training significantly reduced pain severity and activity in the tibialis anterior, peroneus longus, and gastrocnemius medialis muscles during the ascending phase of the dynamic single-leg squat test. On the basis of the findings, 8 weeks of inspiratory muscle training may constitute useful rehabilitation for reducing excessive activity in ankle joint muscles and aiding chronic low-back pain recovery.

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Connor A. Burton, Robert J. Arthur, Matthew J. Rivera and Cameron J. Powden

Context: Chronic ankle instability (CAI) is one of the most common chronic conditions in the world, resulting in millions of dollars contributed to the health care system. Joint mobilizations have been shown to effectively improve patient and disease-specific impairments secondary to CAI. The ability for patients to complete an effective manual therapy intervention without the need for continuous visits to a health care provider can alleviate burdens on the health care system and improve patient satisfaction. Objective: To examine the effect of clinician-applied Maitland talocrural joint mobilization and self-mobilization (Self-Mob) on dorsiflexion range of motion (DFROM), dynamic balance, strength, and perceived function in those with CAI. Design: Single-blind randomized trial. Setting: Research laboratory. Participants: A total of 18 participants (7 males and 11 females; age = 20.78 [2.02] y, height = 67.66 [3.83] cm, limb length = 87.74 [5.05] cm) with self-reported CAI participated. Interventions: The participants received 6 interventions over a 2-week period. The participants received either Maitland grade III anterior-to-posterior talocrural joint mobilizations or weight-bearing lunge Self-Mob. Each intervention consisted of four 2-minute sets, with a 1-minute rest between sets. Main Outcome Measures: The DFROM (weight-bearing lunge), dynamic balance (Y-Balance Test), isometric strength, Foot and Ankle Ability Measure Quick, Disablement of the Physically Active modified, Fear Avoidance Beliefs Questionnaire, and Tampa Scale of Kinesiophobia-11 were measured preintervention and postintervention. Results: Dynamic balance, isometric strength, and perceived function significantly improved in both groups at postintervention. The DFROM significantly improved in the Self-Mob group. Higher individual responder rates were demonstrated within the Self-Mob group compared with clinician-applied mobilizations. Conclusions: Clinician-applied mobilizations and Self-Mobs are effective interventions for improving dynamic balance, isometric strength, and perceived function. Application of Self-Mobs can effectively improve DFROM compared with joint mobilization. Self-Mobs may be an effective intervention to incorporate into a home care plan.

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Shogo Takano, Yoshitaka Iwamoto, Junya Ozawa and Nobuhiro Kito

Context: Previous studies have reported that the incidence of patellofemoral pain in women is 2.2 times higher than that in men. Lower hip frontal dynamic joint stiffness in women may be related to the magnitude of hip adduction and internal rotation associated with patellofemoral pain. Objective: To identify sex differences in hip frontal dynamic joint stiffness and examine the relationship between hip frontal dynamic joint stiffness and hip adduction and internal rotation during gait. Design: Cross-sectional study. Setting: University campus. Participants: A total of 80 healthy volunteers (40 women and 40 men) participated in this study. Intervention(s): Kinematic and kinetic data during gait were collected using a motion capture system and force plates. Main Outcome Measures: Hip frontal dynamic joint stiffness, hip adduction, and hip internal rotation were calculated during gait. Results: Women demonstrated lower hip frontal dynamic joint stiffness than men during gait (P < .01). They also displayed decreased hip frontal dynamic joint stiffness associated with increased hip adduction (r = −.85, P < .001) and internal rotation (r = −.48, P < .001). Conversely, in men, decreased hip frontal dynamic joint stiffness was associated with increased hip adduction (r = −.74, P < .001) but not internal rotation (r = .17, P = .28). Conclusions: Sex differences between hip frontal dynamic joint stiffness and hip internal rotation during gait may contribute to the increased incidence of patellofemoral pain in women.