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Volume 38 (2022): Issue 3 (Jun 2022)

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Effect of Age on Thoracic, Lumbar, and Pelvis Coordination During Trunk Flexion and Extension

Rumit S. Kakar, Seth Higgins, Joshua M. Tome, Natalie Knight, Zachary Finer, Zachary Doig, and Yumeng Li

The purpose of this study was to investigate normative and age-related differences in trunk and pelvis kinematics and intersegmental coordination during sagittal plane flexion–extension. Trunk and pelvis kinematics were recorded while 76 participants performed a maximal range of motion task in the sagittal plane. Cross-correlation was calculated to determine the phase lag between adjacent segment motion, and coupling angles were calculated using vector coding and classified into one of 4 coordination patterns: in-phase, antiphase, superior, and inferior phase. A 2-way mixed-model multivariate analysis of variance was used to compare lumbar spine and pelvis angular kinematics, phase lags, and cross-correlation coefficients between groups. Young participants exhibited greater trunk range of motion compared with middle-aged participants. The lumbar spine and pelvis were predominantly rotating with minimum phase lag during flexion and extension movement for both age groups, and differences in coordination between the groups were seen during hyperextension and return to upright position. In conclusion, middle-aged adults displayed lower range of motion but maintained similar movement patterns to young adults, which could be attributed to protective mechanisms. Healthy lumbar and pelvis movement patterns are important to understand and need to be quantified as a baseline, which can be used to develop rehabilitation protocols for individuals with spinal ailments.

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Medial and Lateral Tibiofemoral Compressive Forces in Patients Following Unilateral Total Knee Arthroplasty During Stationary Cycling

Erik T. Hummer, Tanner Thorsen, Joshua T. Weinhandl, Jeffrey A. Reinbolt, Harrold Cates, and Songning Zhang

Patients following unilateral total knee arthroplasty (TKA) display interlimb differences in knee joint kinetics during gait and more recently, stationary cycling. The purpose of this study was to use musculoskeletal modeling to estimate total, medial, and lateral tibiofemoral compressive forces for patients following TKA during stationary cycling. Fifteen patients of unilateral TKA, from the same surgeon, participated in cycling at 2 workrates (80 and 100 W). A knee model (OpenSim 3.2) was used to estimate total, medial, and lateral tibiofemoral compressive forces for replaced and nonreplaced limbs. A 2 × 2 (limb × workrate) and a 2 × 2 × 2 (compartment × limb × workrate) analysis of variance were run on the selected variables. Peak medial tibiofemoral compressive force was 23.5% lower for replaced compared to nonreplaced limbs (P = .004, G = 0.80). Peak medial tibiofemoral compressive force was 48.0% greater than peak lateral tibiofemoral compressive force in nonreplaced limbs (MD = 344.5 N, P < .001, G = 1.6) with no difference in replaced limbs (P = .274). Following TKA, patients have greater medial compartment loading on their nonreplaced compared to their replaced limbs and ipsilateral lateral compartment loading. This disproportionate loading may be cause for concern regarding exacerbating contralateral knee osteoarthritis.

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Associations Between Lower Limb Isometric Torque, Isokinetic Torque, and Explosive Force With Phases of Reactive Stepping in Young, Healthy Adults

Tyler M. Saumur, Jacqueline Nestico, George Mochizuki, Stephen D. Perry, Avril Mansfield, and Sunita Mathur

This study aimed to determine the relationship between lower limb muscle strength and explosive force with force plate–derived timing measures of reactive stepping. Nineteen young, healthy adults responded to 6 perturbations using an anterior lean-and-release system. Foot-off, swing, and restabilization times were estimated from force plates. Peak isokinetic torque, isometric torque, and explosive force of the knee extensors/flexors and plantar/dorsiflexors were measured using isokinetic dynamometry. Correlations were run based on a priori hypotheses and corrected for the number of comparisons (Bonferroni) for each variable. Knee extensor explosive force was negatively correlated with swing time (r = −.582, P = .009). Knee flexor peak isometric torque also showed a negative association with restabilization time (r = −.459, P = .048); however, this was not statistically significant after correcting for multiple comparisons. There was no significant relationship between foot-off time and knee or plantar flexor explosive force (P > .025). These findings suggest that there may be utility to identifying specific aspects of reactive step timing when studying the relationship between muscle strength and reactive balance control. Exercise training aimed at improving falls risk should consider targeting specific aspects of muscle strength depending on specific deficits in reactive stepping.

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Characterizing Lumbar Spine Kinematics and Kinetics During Simulated Low-Speed Rear Impact Collisions

Kayla M. Fewster, Jackie D. Zehr, Chad E. Gooyers, Robert J. Parkinson, and Jack P. Callaghan

Background: Recent work has demonstrated that low back pain is a common complaint following low-speed collisions. Despite frequent pain reporting, no studies involving human volunteers have been completed to examine the exposures in the lumbar spine during low-speed rear impact collisions. Methods: Twenty-four participants were recruited and a custom-built crash sled simulated rear impact collisions, with a change in velocity of 8 km/h. Randomized collisions were completed with and without lumbar support. Inverse dynamics analyses were conducted, and outputs were used to generate estimates of peak L4/L5 joint compression and shear. Results: Average (SD) peak L4/L5 compression and shear reaction forces were not significantly different without lumbar support (compression = 498.22 N [178.0 N]; shear = 302.2 N [98.5 N]) compared to with lumbar support (compression = 484.5 N [151.1 N]; shear = 291.3 N [176.8 N]). Lumbar flexion angle at the time of peak shear was 36° (12°) without and 33° (11°) with lumbar support. Conclusion: Overall, the estimated reaction forces were 14% and 30% of existing National Institute of Occupational Safety and Health occupational exposure limits for compression and shear during repeated lifting, respectively. Findings also demonstrate that, during a laboratory collision simulation, lumbar support does not significantly influence the total estimated L4/L5 joint reaction force.

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Lower Limb Extension Power is Associated With Slope Walking Joint Loading Mechanics in Older Adults

Peter B. Thomsen, Jacob W. Aumeier, Chelsey A. Wilbur, Evan G. Oro, Hunter B. Carlson, and Jesse C. Christensen

Fall-related injuries are associated with muscle weakness and common during slope walking in older adults. However, no study has evaluated the relationship between muscle weakness, measured by maximal lower limb extension power, and older adults’ ability to navigate slope walking for a better understanding of fall prevention. Therefore, the purpose of this study was to investigate the association between maximal lower limb extension power and joint mechanics during slope walking. Fifteen healthy older adults were tested. Lower limb extension power was measured using the Leg Extension Power Rig. Kinematic and kinetic analysis was performed during level (0°), incline (10°), and decline (10°) slope walking. Greater maximal lower limb extension power was significantly (p < .050; Cohen’s f 2 > 0.35) associated with multiple kinetic and kinematic joint mechanic variables across stance phase of the gait cycle during level, incline, and decline walking. These findings will allow clinicians to better educate patients and develop interventions focused on fall prevention and improving functional mobility in older adults.

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Gait Slip-Induced Fall-Type Assessment Based on Regular Gait Characteristics in Older Adults

Shuaijie Wang, Yi-Chung (Clive) Pai, and Tanvi Bhatt

Older adults could experience split falls or feet-forward falls following an unexpected slip in gait due to different neuromuscular vulnerabilities, and different intervention strategies would be required for each type of faller. Thus, this study aimed to investigate the key factors affecting the fall types based on regular gait pattern. A total of 105 healthy older adults who experienced a laboratory-induced slip and fall were included. Their natural walking trial immediately prior to the novel slip trial was analyzed. To identify the factors related to fall type, gait characteristics and demographic factors were determined using univariate logistic regression, and then stepwise logistic regression was conducted to assess the slip-induced fall type based on these factors. The best fall-type prediction model involves gait speed and recovery foot angular velocity, which could predict 70.5% of feet-forward falls and 86.9% of split falls. Body mass index was also a crucial fall-type prediction with an overall prediction accuracy of 70.5%. Along with gait parameters, 84.1% of feet-forward falls and 78.7% of split falls could be predicted. The findings in this study revealed the determinators related to fall types, which enhances our knowledge of the mechanism associated to slip-induced fall and would be helpful for the development of tailored interventions for slip-induced fall prevention.

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Head Impact Kinematics and Brain Deformation in Paired Opposing Youth Football Players

Gabriella M. Milef, Logan E. Miller, Daniella M. DiGuglielmo, Tanner D. Payne, Tanner M. Filben, Jillian E. Urban, and Joel D. Stitzel

Head impact exposure is often quantified using peak resultant kinematics. While kinematics describes the inertial response of the brain to impact, they do not fully capture the dynamic brain response. Strain, a measure of the tissue-level response of the brain, may be a better predictor of injury. In this study, kinematic and strain metrics were compared to contact characteristics in youth football. Players on 2 opposing teams were instrumented with head impact sensors to record impact kinematics. Video was collected to identify contact scenarios involving opposing instrumented players (ie, paired contact scenarios) and code contact characteristics (eg, player role, impact location). A previously validated, high-resolution brain finite element model, the atlas-based brain model, was used to simulate head impacts and calculate strain metrics. Fifty-two paired contact scenarios (n = 105 impacts) were evaluated. Lighter players tended to have greater biomechanical metrics compared to heavier players. Impacts to the top of the helmet were associated with lower strain metrics. Overall, strain was better correlated with rotational kinematics, suggesting these metrics may be better predictors of the tissue-level brain response than linear kinematics. Understanding the effect of contact characteristics on brain strain will inform future efforts to improve sport safety.

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Erratum. Shoulder Kinesio Taping Does Not Change Biomechanical Deficits Associated With Scapular Dyskinesis

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Shoulder Kinesio Taping Does Not Change Biomechanical Deficits Associated With Scapular Dyskinesis

Sevgi Sevi Yeşilyaprak, Ertuğrul Yüksel, Melike Gizem Kalaycı, Nuri Karabay, and Lori A. Michener

Observable scapular dyskinesis is associated with biomechanical deficits. Preventative interventions aimed at correcting these deficits may aid in preventing the development and resolution of shoulder pain. Our purpose was to investigate the effects of kinesio taping (KT) on common biomechanical deficits associated with scapular dyskinesis and shoulder pain. Participants (n = 51) with observable scapular dyskinesis, and without shoulder pain were randomized to KT, KT-placebo, or a no-treatment control group. Measurements taken before, immediately after taping, and 3 days later included pectoralis minor muscle length, lower trapezius muscle strength, scapular upward rotation angle at 0° to 120° in scapular plane humeral elevation and acromiohumeral distance. There were no changes in scapular upward rotation, lower trapezius strength, and acromiohumeral distance immediately after taping or 3 days later compared to baseline (P > .05). The pectoralis minor increased in length in the KT group on day 3 compared to directly after taping (P = .03), but no difference between groups or interaction between time and group were determined (P > .05). Scapular dyskinesis prevalence did not change over time in any group (P > .05). In people with scapular dyskinesis free from shoulder pain, KT applied to the shoulder cannot be recommended to ameliorate the biomechanical deficits associated with shoulder pain.