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Relationship Between Shoulder Pain and Joint Reaction Forces and Muscle Moments During 2 Speeds of Wheelchair Propulsion

Li-Shan Chang, Xiong-Wen Ke, Weerawat Limroongreungrat, and Yong Tai Wang

The purpose of this study was to determine shoulder joint reaction forces and muscle moments during 2 speeds (1.3 and 2.2 m/s) of wheelchair propulsion and to investigate the relationship between joints reaction forces, muscle moments, and shoulder pain. The measurements were obtained from 20 manual wheelchair users. A JR3 6-channel load sensor (±1% error) and a Qualisys system were used to record 3-dimensional pushrim kinetics and kinematics. A 3-dimensional inverse dynamic model was generated to compute joint kinetics. The results demonstrated significant differences in shoulder joint forces and moments (P < .01) between the 2 speeds of wheelchair propulsion. The greatest peak shoulder joint forces during the drive phase were anterior directed (Fy, 184.69 N), and the greatest joint moment was the shoulder flexion direction (flexion moment, 35.79 N·m) at 2.2 m/s. All the shoulder joint reaction forces and flexion moment were significantly (P < .05) related to shoulder pain index. The forces combined in superior and anterior direction found at the shoulder joint may contribute to the compression of subacromial structure and predispose manual wheelchair users to potential rotator cuff impingement syndrome.

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Weighted Vest Loads Do Not Elicit Changes in Spatial-Temporal Gait Parameters in Children and Adolescents With Autism

Alyssa N. Olivas, Emily A. Chavez, and Jeffrey D. Eggleston

Weighted vests have been used primarily as behavioral interventions for children and adolescents with autism. Contemporary research has begun to examine weighted vest effects on movement. Previous research in children with neurotypical development revealed 15% body mass loads modified spatial-temporal gait characteristics; however, a value applicable to children and adolescents with autism has not been established. The purpose of this study was to establish an appropriate mass value by examining spatial-temporal gait parameters in children and adolescents with autism with various loads in a weighted vest. Nine children and adolescents with autism, aged 8–17, walked without a weighted vest, with 5%, 10%, 15%, and 20% body mass while spatial-temporal data were captured. Repeated-measures analysis of variance (α = .05) were conducted among conditions for each variable, with a Holm–Bonferroni method correction. Analysis revealed significant decreases in right step length, but no differences in stride width, left step length, double-limb support time, or stride velocity were observed. Due to insignificant findings, an appropriate mass value could not be determined for weighted vests for children with autism. However, unchanged spatial-temporal gait parameters with increasing loads could be clinically relevant as weighted vest loads of 10% are typically used for behavioral interventions.

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Differences in Muscle Demand and Joint Contact Forces Between Running and Skipping

Sarah A. Roelker, Paul DeVita, John D. Willson, and Richard R. Neptune

Skipping has been proposed as a viable cross-training exercise to running due to its lower knee contact forces and higher whole-body energy expenditure. However, how individual muscle forces, energy expenditure, and joint loading are affected by differences in running and skipping mechanics remains unclear. The purpose of this study was to compare individual muscle forces, energy expenditure, and lower extremity joint contact forces between running and skipping using musculoskeletal modeling and simulations of young adults (n = 5) performing running and skipping at 2.5 m·s−1 on an instrumented treadmill. In agreement with previous work, running had greater knee and patella contact forces than skipping which was accompanied by greater knee extensor energetic demand. Conversely, skipping had greater ankle contact forces and required greater energetic demand from the uniarticular ankle plantarflexors. There were no differences in hip contact forces between gaits. These findings further support skipping as a viable alternative to running if the primary goal is to reduce joint loading at the commonly injured patellofemoral joint. However, for those with ankle injuries, skipping may not be a viable alternative due to the increased ankle loads. These findings may help clinicians prescribe activities most appropriate for a patient’s individual training or rehabilitation goals.

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Mechanisms of Achilles Tendon Rupture in National Basketball Association Players

Adam J. Petway, Matthew J. Jordan, Scott Epsley, and Philip Anloague

A systematic search was performed of online databases for any Achilles tendon (AT) injuries occurring within the National Basketball Association (NBA). Video was obtained of injuries occurring during competition and downloaded for analysis in Dartfish. NBA athletes (n = 27) were identified with AT rupture over a 30-year period (1991–2021). Of the 27 NBA athletes found to have AT ruptures (mean age: 29.3 [3.3] y; average time in the NBA: 8.5 [3.8] y), 15 in-game videos were obtained for analysis. Noncontact rupture was presumed to have occurred in 12/13 cases. Eight of the 13 athletes had possession of the ball during time of injury. The ankle joint of the injured limb for all 13 athletes was in a dorsiflexed position during the time of injury (47.9° [6.5°]). All 13 athletes performed a false-step mechanism at time of injury where they initiated the movement by taking a rearward step posterior to their center of mass with the injured limb before translating forward. NBA basketball players that suffered AT ruptures appeared to present with a distinct sequence of events, including initiating a false step with ankle dorsiflexion of the injured limb at the time of injury.

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Volume 38 (2022): Issue 5 (Oct 2022)

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The Influence of Cell Phone Usage on Dynamic Stability of the Body During Walking

Hamed Shahidian, Rezaul Begg, and David C. Ackland

Dual-task walking and cell phone usage, which is associated with high cognitive load and reduced situational awareness, can increase risk of a collision, a fall event, or death. The objective of this study was to quantify the effect of dual-task cell phone talking, texting, and reading while walking on spatiotemporal gait parameters; minimum foot clearance; and dynamic stability of the lower limb joints, trunk, and head. Nineteen healthy male participants walked on an instrumented treadmill at their self-selected speed as well as walking while simultaneously (1) reading on a cell phone, (2) texting, and (3) talking on a cell phone. Gait analyses were performed using an optical motion analysis system, and dynamic stability was calculated using the Maximum Lyapunov Exponent. Dual-task cell phone usage had a significant destabilizing influence on the lower limb joints during walking. Cell phone talking while walking significantly increased step width and length and decreased minimum foot clearance height (P < .05). The findings suggest that dual-task walking and cell phone conversation may present a greater risk of a fall event than texting or reading. This may be due to the requirements for more rapid information processing and cognitive demand at the expense of motor control of joint stability.

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Nonlinear Analyses Distinguish Load Carriage Dynamics in Walking and Standing: A Systematic Review

Kolby J. Brink, Kari L. McKenzie, and Aaron D. Likens

Load carriage experiments are typically performed from a linear perspective that assumes that movement variability is equivalent to error or noise in the neuromuscular system. A complimentary, nonlinear perspective that treats variability as the object of study has generated important results in movement science outside load carriage settings. To date, no systematic review has yet been conducted to understand how load carriage dynamics change from a nonlinear perspective. The goal of this systematic review is to fill that need. Relevant literature was extracted and reviewed for general trends involving nonlinear perspectives on load carriage. Nonlinear analyses that were used in the reviewed studies included sample, multiscale, and approximate entropy; the Lyapunov exponent; fractal analysis; and relative phase. In general, nonlinear tools successfully distinguish between unloaded and loaded conditions in standing and walking, although not in a consistent manner. The Lyapunov exponent and entropy were the most used nonlinear methods. Two noteworthy findings are that entropy in quiet standing studies tends to decrease, whereas the Lyapunov exponent in walking studies tends to increase, both due to added load. Thus, nonlinear analyses reveal altered load carriage dynamics, demonstrating promise in applying a nonlinear perspective to load carriage while also underscoring the need for more research.

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The Effects of Cadence Manipulation on Joint Kinetic Patterns and Stride-to-Stride Kinetic Variability in Female Runners

Cheyanne Massie, Kelsey Redman, Samantha Casper, Danielle Wissink, Renee Dade, Anna Lowery, Kim Ross, Kanikkai Steni Balan Sackiriyas, and Thomas Gus Almonroeder

Altering running cadence is commonly done to reduce the risk of running-related injury/reinjury. This study examined how altering running cadence affects joint kinetic patterns and stride-to-stride kinetic variability in uninjured female runners. Twenty-four uninjured female recreational runners ran on an instrumented treadmill with their typical running cadence and with a running cadence that was 7.5% higher and 7.5% lower than typical. Ground reaction force and kinematic data were recorded during each condition, and principal component analysis was used to capture the primary sources of variability from the sagittal plane hip, knee, and ankle moment time series. Runners exhibited a reduction in the magnitude of their knee extension moments when they increased their cadence and an increase in their knee extension moments when they lowered their cadence compared with when they ran with their typical cadence. They also exhibited greater stride-to-stride variability in the magnitude of their hip flexion moments and knee extension moments when they deviated from their typical running cadence (ie, running with either a higher or lower cadence). These differences suggest that runners could alter their cadence throughout a run in an attempt to limit overly repetitive localized tissue stresses.

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Comparison of Kinematic Movement Patterns Between 2 Subgroups of Females With Low Back Pain and Healthy Women During Sit-to-Stand and Stand-to-Sit

Neda Orakifar, Mohammad Jafar Shaterzadeh-Yazdi, Reza Salehi, Mohammad Mehravar, Neda Namnik, and Seyyed Arash Haghpanah

The purpose of study was to compare the kinematic patterns of the thoracic, lumbar, and pelvis segments and hip joints between 2 low back pain subgroups and healthy women during sit-to-stand and stand-to-sit. Kinematic data of 44 healthy women and 2 subgroups of females with low back pain in 2 subgroups of movement system impairment model (rotation-extension [Rot.Ext] and rotation-flexion [Rot.Flex]) were recorded. Participants performed sit-to-stand and stand-to-sit at a preferred speed. Each task was divided into a pre buttock lifted off/on (pre-BOff/n) phase and a post-BOff/n phase. The Rot.Ext subgroup showed greater range of motion in the thoracic during pre-BOff phase of sit-to-stand (P < .001) and pre-BOn phase of stand-to-sit (P = .01) compared to the other 2 groups. The Rot.Flex subgroup displayed limited left hip joint excursion during sit-to-stand pre-BOff (P = .04) and stand-to-sit post-BOn phases (P = .02). The Rot.Flex subgroup showed greater pelvis tilt excursion during sit-to-stand post-BOff (P = .04) and stand-to-sit pre-BOn (P = .01) and post-BOn phases (P = .01). In subgroups of women with chronic low back pain, there were kinematic changes in adjacent body segments/joints of lumbar spine during sit-to-stand and stand-to-sit tasks.

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Effect of Load on Muscle Activity, Kinematics, and Force Production During the Reverse Hyperextension Exercise

Michael A. Lawrence, Matthew J. Somma, and Brian T. Swanson

The reverse hyperextension exercise is used to strengthen posterior chain musculature without axially loading the spine; however, there are no suggestions for loading. Twenty recreationally active individuals (13 males and 7 females; aged 25.4 [2.5] y; height 1.76 [0.09] m; mass 79.3 [15.8] kg) performed 2 sets of 10 repetitions with 50%, 100%, and 150% of bodyweight. Surface electromyography measured erector spinae, gluteus maximus, and biceps femoris activity. Motions of the trunk, lower extremities, and reverse hyperextension exercise pendulum were tracked. A 1-way repeated-measures analysis of variance was used to analyze differences. Few differences were found between 100% and 150% loads; however, heavier loads resulted in increased hip (5.0°) and trunk (4.0°) flexion compared with the 50% load. Similar patterns emerged for peak and integrated muscle activity, with erector spinae and gluteus maximus activity greater in the 100% and 150% loads than in the 50% load, and biceps femoris activation increasing as load increased. Peak force significantly (P < .001) increased with 100% (28% [31%]) and 150% (34% [40%]) loads compared with the 50% load. Findings suggest the reverse hyperextension exercise targets posterior chain musculature, but increasing loads does not linearly increase force and muscle activation.