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.
Cheyanne Massie, Kelsey Redman, Samantha Casper, Danielle Wissink, Renee Dade, Anna Lowery, Kim Ross, Kanikkai Steni Balan Sackiriyas, and Thomas Gus Almonroeder
Cindy H.P. Sit, Wendy Y.J. Huang, Stephen H.S. Wong, Martin C.S. Wong, Raymond K.W. Sum, and Venus M.H. Li
Background: Following the 2019 Hong Kong Para Report Card, the 2022 Hong Kong Para Report Card aimed to provide an updated and evidence-based assessment for nine indicators related to physical activity in children and adolescents with special educational needs and to assess the results using a SWOT (strengths, weaknesses, opportunities, and threats) analysis. Methods: Using a systematic process, the best available data on nine indicators were searched from the past 10 years and were assessed by a research work group. Letter grades were assigned and considered by stakeholders and auditors. Results: Four indicators were assigned a letter grade (overall physical activity: F [mixed device-measured and self-reported data]; sedentary behaviors: D [device-measured data]; active transportation: D−; government strategies & investment: C+). SWOT analysis highlighted opportunities for facilitating children and adolescents with special educational needs to achieve health recommendations. Conclusion: There were deteriorating trends in physical activity and sedentary behaviors. Effective, multilevel, and cross-sector interventions are recommended to promote active behavior in children and adolescents with special educational needs.
Susann Arnell, Kajsa Jerlinder, and Lars-Olov Lundqvist
Background: Participation in physical activity among adolescents with autism is often conditional. However, there is a lack of methods for identifying these specific conditions. Therefore, the purpose of this study was to develop and investigate the feasibility of a Q-sort tool to map individual-specific conditions for participation in physical activity among adolescents with autism and to identify different viewpoints regarding conditions for such participation. Method: An exploratory mixed-methods design was employed to investigate the feasibility of using Q methodology and the Q-sort procedure to identify what individual-specific conditions are important for participation in physical activity for adolescents with autism. Results: The adolescents ranked the statements with varying levels of ease. Two viewpoints were identified: Autonomous participation without surprises and Enjoyment of activity in a safe social context. Conclusion: Q-sort is a feasible method for mapping conditions for participation, which can guide the development of tailored physical activity interventions.
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.
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.
Luke Nigro and Elisa S. Arch
Dynamic joint stiffness (or simply “stiffness”) is a customization criteria used to tune mechanical properties of orthotic and prosthetic devices. This study examines metatarsophalangeal (MTP) joint stiffness during the toe-rocker phase of barefoot walking and establishes baseline characteristics of MTP joint stiffness. Ten healthy individuals walked at 4 speeds (0.4, 0.6, 0.8, and 1.0 statures·s−1) over level ground. MTP sagittal plane joint angles and moments were calculated during the toe-rocker phase of stance. Least-squares linear regressions were conducted on the MTP moment versus angle curve to determine joint stiffness during early toe rocker and late toe rocker. Multilevel linear models were used to test for statistically significant differences between conditions. Early toe rocker stiffness was positive, while late toe rocker was negative. Both early toe rocker and late toe rocker stiffness increased in magnitude significantly with speed. This study establishes baseline characteristics of MTP joint stiffness in healthy walking, which previously had not been examined through a range of controlled walking speeds. This information can be used in the future as design criteria for orthotic and prosthetic ankle and ankle–foot devices that can imitate, support, and facilitate natural human foot motion during walking better than existing devices.
Matthew Slopecki, Fariba Hasanbarani, Chen Yang, Christopher A. Bailey, and Julie N. Côté
Fatigue at individual joints is known to affect interjoint coordination during repetitive multijoint tasks. However, how these coordination adjustments affect overall task stability is unknown. Twelve participants completed a repetitive pointing task at rest and after fatigue of the shoulder, elbow, and trunk. Upper-limb and trunk kinematics were collected. Uncontrolled manifold framework was applied to a kinematic model to link elemental variables to endpoint fingertip position. Mixed and one-way analysis of variances determined effects (phase and fatigue location) on variance components and synergy index, respectively. The shoulder fatigue condition had the greatest impact in causing increases in variance components and a decreased synergy index in the late phase of movement, suggesting more destabilization of the interjoint task caused by shoulder fatigue.
San Hong, Jieun Yang, Donghyun Kim, and Yongho Lee
The purpose of this study was to draw consensus among an expert panel regarding essential elements of an accessible fitness center guide for people with intellectual disabilities that will enable them to engage in physical activity fully and effectively. The study was situated in the socioecological model of disability. Researchers drew expert consensus regarding the essential features of accessible guides in fitness environments. A three-round Delphi procedure was used, involving repeated circulation of the questionnaire to an expert panel (N = 33). The panel was asked to rate the importance and adequacy of 66 items regarding the accessible fitness guide. A consensus was reached regarding 43 items after three rounds. The items include 7 body-weight exercises, 2 machine exercises, 12 environment-related items, 15 exercise preparations, 4 social etiquettes, and 3 emergencies.
Cagla Ozkul, Kader Eldemir, Sefa Eldemir, Muhammed Seref Yildirim, Fettah Saygili, Arzu Guclu-Gunduz, and Ceyla Irkec
This study aimed to investigate the relationship of sit-to-stand and walking performance with leg muscle strength and core muscle endurance in people with multiple sclerosis (PwMS) with mild disabilities. In this study, 49 PwMS (Expanded Disability Status Scale score = 1.59 ± 0.79) and 26 healthy controls were enrolled. The functional performances, including sit-to-stand and walking performances, were evaluated with the five-repetition sit-to-stand test, timed up and go test, and 6-min walking test. The PwMS finished significantly slower five-repetition sit-to-stand, timed up and go, and 6-min walking test than the healthy controls. In addition, the significant contributors were the weakest trunk lateral flexor endurance for five-repetition sit-to-stand; the Expanded Disability Status Scale score, and the weakest hip adductor muscle for timed up and go; the weakest hip extensor muscles strength for 6-min walking test. The functional performances in PwMS, even with mild disabilities, were lower compared with healthy controls. Decreases in both leg muscle strength and core muscle endurance are associated with lower functional performance in PwMS.
Ashwini Kulkarni, Chuyi Cui, Shirley Rietdyk, and Satyajit Ambike
Maintaining a consistent relationship between each footfall and the body’s motion is a key mechanism to maintain balance while walking. However, environmental features, for example, puddles/obstacles, impose additional constraints on foot placement. This study investigated how healthy young individuals alter foot placements to simultaneously manage body-centric and environmental constraints during an obstacle-crossing task. Consistent step length promotes balance for all steps, whereas accurate foot placement around the obstacle is essential to avoid a trip. While crossing an obstacle, any error in positioning one foot relative to the obstacle can be compensated by selecting the placement of the subsequent step. However, compensation will necessarily alter step length from its average value. The interstep covariance index computed from two consecutive foot placements was used to quantify this tradeoff between body-centric and environmental constraints for six consecutive steps while approaching, crossing, and resuming unobstructed gait after crossing the obstacle. The index declined only when either one or both feet were adjacent to the obstacle. The decline was driven in part by a tendency toward higher step length variability. Thus, changes in the stepping patterns to address the environmental constraint occurred at the cost of the body-centric constraint. However, the step length never ceased to be controlled; the interstep covariance index was positive for all steps. Overall, participants adapted foot placement control to account for the larger threat to balance. The environmental constraint was prioritized only when a potential trip posed greater threat to balance compared with the threat posed by variable step length.