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The Effect of an Overhead External Load Lifting and Lowering on Dynamic Postural Control in Subgroups of Low Back Pain

Majid Shahbazi, Javad Sarrafzadeh, Ismail Ebrahimi Takamjani, and Hossein Negahban

Background: Understanding postural control in low back pain (LBP) subgroups can help develop targeted interventions to improve postural control. The studies on this topic are limited. Therefore, the primary purpose of this study was to compare the postural control of LBP subgroups with healthy individuals during overhead load lifting and lowering. Methods: In this cross-sectional study, the participants were 52 with LBP and 20 healthy. The LBP patients were classified based on the O’Sullivan classification system into 21 flexion patterns and 31 active extension patterns. The participants lifted the box from their waists to their overheads and lowered it to their waists. Changes in postural control parameters were measured with a force plate system. Results: The results of the analysis of variance showed that during load lifting, the mediolateral phase plane (p = .044) and the mean total velocity (p = .029) had significant differences between flexion patterns and healthy. Also, the load-lowering results showed that active extension patterns, compared with healthy, had significant differences in the anteroposterior–mediolateral phase plane (p = .042). The patients showed less postural sway than the healthy. Conclusions: The results in this work highlight the importance of identifying the homogenous subgroups in LBP and support the classification of heterogeneous LBP. Different subgroups exhibit different postural control behaviors. These behaviors can be due to the loading of various tissues during different tasks.

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Motor Transfer and Proactive Interference in Cycling With a Noncircular Chainring

Thomas Haab, Peter Leinen, and Stefan Panzer

Athletes must transfer their performance when changing equipment due to innovative developments in sports technology. This kind of transfer has received only moderate attention. The aim of this study was to examine whether a mechanical change in sports equipment disturbs an athlete’s performance and affects biomechanical and neurophysiological parameters. Therefore, an experiment was conducted in which 36 participants in three groups pedaled at 70 rounds per minute on a cycling ergometer with a circular and a noncircular (NC) chainring. The dependent variables were the total variability of the cadence, torque effectiveness, and muscle cocontraction (electromyographic cocontraction) of four antagonistic acting muscle pairs. Data were recorded during an acquisition phase, a transfer phase, and a retention phase. The results revealed that practice on a circular chainring induces a positive transfer on the NC chainring for total variability without a proactive interference effect. Torque effectiveness did not change within or between groups during the acquisition, transfer, and retention phases. Torque effectiveness and electromyographic cocontraction were not affected when the chainrings were altered from Day 1 to Day 2. During the retention phase, electromyographic cocontraction was higher when using the NC chainring, but the difference was small in absolute terms. The results regarding transfer and proactive interference seem to be strongly dependent on the movement task and the change in sports equipment. Transfer from the circular to NC chainring indicates refined neuromuscular control and improved movement coordination.

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A New Way to Restrict Free Leg Movement During Unilateral Vertical Jump Test

Christian Schmidt, Mike Perroulaz, Yago Perez, Jérémie Rosset, Gabriel Wüthrich, Davide Malatesta, and Pierre Samozino

The purpose of this investigation was (1) to test the effect of movement restriction of the free leg during unilateral vertical jump on performance and power output comparing 2 different jump techniques: flexed (Classic technique) and straight (FC Luzern technique) free leg, and (2) to test the correlation between performance and power output obtained using these 2 techniques. Twenty elite soccer players performed squat (SJ) and countermovement (CMJ) jumps on each leg. The jump height and peak power output were compared between the 2 techniques for both legs. The jump height and peak power were significantly higher for the classic test for SJ and CMJ (P < .001) with no side effects or interactions. The angular range of motion of the free leg was higher for the Classic test than for the FC Lucerne test (P < .001), with no difference in the angular range of motion of the trunk. A moderate correlation was found between the 2 techniques on peak power (SJ: r = .626; CMJ: r = .649) and jump height (SJ: r = .742; CMJ: r = .891). Consequently, FC Lucerne technique, limiting the contribution of the free leg, is more appropriate to assess lower limb strength capacities during unilateral jump test.

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Erratum. Personality and Attitudinal Predictors of Sportspersonship in Recreational Sport

Journal of Clinical Sport Psychology

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Exploring Physical Educators’ Self-Efficacy to Teach Students With Disabilities in General Physical Education

Lindsey A. Nowland

The purpose of this study was to explore the ways in which in-service physical education teachers construct their self-efficacy beliefs toward teaching students with disabilities in general physical education classes. Using a qualitative descriptive approach situated within self-efficacy theory, data were collected via semistructured audio-recorded interviews with 16 in-service physical educators. Three interrelated themes were constructed: (a) The more I do it, the better I feel: the importance of professional experiences; (b) I’ve learned from others: the influence of colleagues; and (c) Being in the general educational setting is a challenge: the impact of contextual factors. Findings supported the influence of the four sources of self-efficacy (i.e., mastery experience, vicarious experience, social persuasion, and affective and physiological state), in addition to potential contextual factors (i.e., class sizes and availability of hands-on support), impacting participants’ self-efficacy to teach students with disabilities in general physical education classes.

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People With Low Back Pain Exhibit Higher Trunk Muscle Activity and Impaired Postural Control During Static and Dynamic Functional Tasks: A Cross-Sectional Study

Sara Salamat, Saeed Talebian, Nader Maroufi, Gitta Kalbassi, Davood Salamat, and Kieran O’Sullivan

The study compared superficial trunk muscle activity and postural control among an active extension subgroup of people with nonspecific chronic low back pain (AE-NSCLBP) with painfree controls during functional tasks. Thirty-two people (17 people with low back pain [LBP] and 15 painfree controls) participated in this study. Muscle activity of 5 trunk muscles and postural control were investigated during both standing tasks (eyes open/closed; single/double-leg balance) and dynamic functional tasks (spinal forward flexion and return, and a sit to stand transfer). Results showed that during single-leg standing, people with AE-NSCLBP exhibit higher muscle activity than painfree controls for 3 trunk muscles, especially with their eyes closed. There were no significant differences in muscle activity between eye conditions during double-leg standing and sit to stand transfer, forward flexion, and return from flexion. The AE-NSCLBP subgroup also demonstrated significantly impaired postural control (lower time to boundary) in 4 of 8 conditions, especially during single-leg standing and with their eyes closed. These findings show people with LBP typically demonstrated greater trunk muscle activity and poorer postural control while maintaining standing posture. This pattern was most evident when the postural challenge was higher, such as single-leg standing or with eyes closed. While this study design cannot infer causality, these findings have implications for LBP rehabilitation, particularly regarding approaches which seek to alter muscle activation among people with LBP.

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Do Sex and Age Influence Scapular and Thoracohumeral Kinematics During a Functional Task Protocol?

Alexander Waslen, Kenzie B. Friesen, and Angelica E. Lang

There is mixed evidence on the role that biological sex plays in shoulder biomechanics despite known differences in musculoskeletal disorder prevalence between males and females. Additionally, advancing age may contribute to shoulder kinematic changes. The purpose of this study was to determine if sex and age influenced scapular and thoracohumeral kinematics during a range of functional tasks. Sixty healthy participants aged 19–63 years (30 males; 30 females) completed a functional task protocol while their upper limb motion was recorded. Scapular and humeral angles were calculated and compared with multiple linear regressions to assess the interaction effects of sex and age. Shoulder kinematics were not different between sex and age groups for many of the functional tasks. However, females had lower humeral external rotation in the overhead lift task (15°, P < .001), and less scapular anterior tilt angles in the forward transfer task (6°, P < .001) than males. Age was positively associated with humeral elevation (R 2 = .330, P < .001) and scapular rotation (R 2 = .299, P < .001) in the Wash Axilla task. There exist some kinematic differences between sex and with advancing age for select functional tasks, which should be considered for musculoskeletal disorder development.

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Increasing Breast Support is Associated With a Distal-to-Proximal Redistribution of Joint Negative Work During a Double-Limb Landing Task

Hailey B. Fong, Alexis K. Nelson, Deirdre McGhee, Kevin R. Ford, and Douglas W. Powell

Female athletes exhibit greater rates of anterior cruciate ligament injury compared with male athletes. Biomechanical factors are suggested to contribute to sex differences in injury rates. No previous investigation has evaluated the role of breast support on landing biomechanics. This study investigates the effect of breast support on joint negative work and joint contributions to total negative work during landing. Thirty-five female athletes performed 5 landing trials in 3 breast support conditions. Lower-extremity joint negative work and relative joint contributions to total negative work were calculated. Univariate analyses of variance were used to determine the effect of breast support on negative joint work values. Increasing levels of breast support were associated with lower ankle negative work (P < .001) and ankle relative contributions (P < .001) and increases in hip negative work (P = .008) and hip relative contributions (P < .001). No changes were observed in total negative work (P = .759), knee negative work (P = .059), or knee contributions to negative work (P = .094). These data demonstrate that the level of breast support affects lower-extremity biomechanics. The distal-to-proximal shift in negative joint work and relative joint contributions may be indicative of a more protective landing strategy for anterior cruciate ligament injuries.

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Personality and Attitudinal Predictors of Sportspersonship in Recreational Sport

Tanya Fozzard and Dara Mojtahedi

Respect and fair treatment among competitors are necessary for maintaining quality and enjoyment in sporting competitions. Yet despite the existence of rules and expectations, many athletes choose to violate such sporting norms. The present study examined whether individual differences in Sportspersonship within recreational sports could be explained by personality and sport-related attitudes. Ultimate Frisbee players (N = 828) completed an online survey consisting of personality (dark triad, HEXACO-60, and Sportspersonship), demographic, and attitudinal questionnaires. Psychopathy was associated with low Sportspersonship, whereas Honesty-Humility, Agreeableness, and Openness to Experience predicted greater Sportspersonship. Additionally, participants holding positive attitudes about the conduct of other players and the efficacy of self-governed regulation displayed higher Sportspersonship. Positive associations between personality traits and Sportspersonship may be attributed to positive views toward cooperation and enjoyment of the experience, whereas negative associations between Psychopathy and Sportspersonship are likely to be linked to the callous and risk-taking nature of such individuals.

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Promoting Physical Activity and Fitness: Supporting Individuals With Childhood-Onset Disabilities

Myung Ha Sur