Journal Of Applied Biomechanics[JOURNAL]
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200 papers
Role of Hip Internal Rotation Range and Foot Progression Angle for Preventing Jones Fracture During Crossover Cutting.
Kikuchi Y, Takabayashi T, Kikumoto T … +4 more , Watanabe T, Suzuki S, Hiratsuka S, Kubo M
J Appl Biomech · 2025 Feb · PMID 39602918 · Publisher ↗
Jones fracture is a common injury in soccer players, caused by overload on the fifth metatarsal (M5) that can occur during crossover cutting. This study aimed to investigate the effects of the hip internal rotation (HIR)...
Jones fracture is a common injury in soccer players, caused by overload on the fifth metatarsal (M5) that can occur during crossover cutting. This study aimed to investigate the effects of the hip internal rotation (HIR) range in passive and dynamic conditions and foot progression angle (FPA) on the forces applied to the M5 during crossover cutting. The study included 20 men with experience playing soccer. The passive HIR was measured in the prone position. A 3-dimensional motion analysis system, force plates, and Footscan were used to measure the angle of the lower limb, including dynamic HIR, FPA, and plantar pressure to the M5, during crossover cutting in the 45° direction. Pearson correlation coefficient was measured to examine the relationship between variables. Passive and dynamic HIR were not related to the plantar pressure on the M5 (P > .05). However, increased FPA in movement direction correlated with a reduction in plantar pressure on the M5 (r = -.56, P < .01). Minimizing the FPA with respect to the new direction during crossover cutting reduced plantar pressure on the M5 and thus could prevent Jones fracture.
The Effect of Step Frequency and Running Speed on the Coordination of the Pelvis and Thigh Segments During Running.
Mesquita RM, Morin JB, Dewolf AH
J Appl Biomech · 2025 Feb · PMID 39577406 · Publisher ↗
This study investigates the specific influence of step frequency (SF) and speed on the coordination between pelvic and thigh movements. Eight recreational male runners ran at different SFs and speeds on an instrumented t...
This study investigates the specific influence of step frequency (SF) and speed on the coordination between pelvic and thigh movements. Eight recreational male runners ran at different SFs and speeds on an instrumented treadmill. The coordination between the pelvis and thigh segments was analyzed using modified vector coding in the sagittal and frontal planes (FPs). Our findings show that hip range of motion increases as a function of SF in the sagittal plane. Pelvic tilt plays a compensatory role in hip extension, particularly at lower SFs. In the FP, pelvic roll increased at lower SFs, whereas the thigh abduction angle was participant dependant. Coordination analysis showed that thigh movements dominated the sagittal plane motion, which was simplified at higher SF. At low SF, the pelvic movements were increased and anticipated, playing a more dominant role in explaining motion. In the FP, pelvic movements dominated the motion. The increase in pelvic motion at low SFs stretches the hip flexors further and for a longer period. The link between SF, pelvic motion, and the risks of running-related injuries in the sagittal and FP is considered. Understanding these could help athletes and sports professionals optimize performance and reduce injury risk.
Effects of Different Inertial Measurement Unit Sensor-to-Segment Calibrations on Clinical 3-Dimensional Humerothoracic Joint Angles Estimation.
Bonfiglio A, Farella E, Tacconi D … +1 more , Bongers RM
J Appl Biomech · 2025 Feb · PMID 39557023 · Publisher ↗
Calibrating inertial measurement units (IMUs) involves converting orientation data from a local reference frame into a clinically meaningful reference system. Several solutions exist but little work has been done to comp...
Calibrating inertial measurement units (IMUs) involves converting orientation data from a local reference frame into a clinically meaningful reference system. Several solutions exist but little work has been done to compare different calibration methods with each other and an optical motion capture system. Thirteen healthy subjects with no signs of upper limb injury were recruited for this study and instrumented with IMU sensors and optical markers. Three IMU calibration methods were compared: N-pose calibration, functional calibration, and manual alignment. Subjects executed simple single-plane single-joint tasks for each upper limb joint as well as more complex multijoint tasks. We performed a 3-way analysis of variance on range of motion error, root mean squared error, and offset to assess differences between calibrations, tasks, and anatomical axes. Differences in the 3 IMU calibrations are minor and not statistically significant for most tasks and anatomical axes, with the exception of the offset interaction calibration × axes (P < .001, ηG2=.056). Specifically, manual alignment gives the best offset estimation on the abduction/adduction and internal/external rotation axes. Therefore, we recommend the use of a static N-pose calibration procedure as the preferred IMU calibration method to model the humerothoracic joint, as this setup is the simplest as it only requires accurate positioning of the trunk sensor.
Enhancing Sprint Performance and Biomechanics in Semiprofessional Football Players Through Repeated-Sprint Training.
Romero V, Castaño-Zambudio A, Ortega-Becerra MA … +3 more , Vázquez-Diz JA, Adalid-Leiva JJ, Jiménez-Reyes P
J Appl Biomech · 2025 Feb · PMID 39547221 · Publisher ↗
Repeated-sprint ability is a significant factor in football performance. Notably, hamstring injuries in football players often occur during sprinting activities and fatigue-inducing conditions. Therefore, the aim of this...
Repeated-sprint ability is a significant factor in football performance. Notably, hamstring injuries in football players often occur during sprinting activities and fatigue-inducing conditions. Therefore, the aim of this study was to examine the impact of repeated-sprint training (RST) on repeated-sprint ability variables and sprint kinematics. Fourteen semiprofessional men's soccer players performed 8 weeks of RST, consisting of 1 to 2 sets of 5 to 8 × 30 m repeated sprints separated by 20 to 30 seconds of recovery. Sprint performance was computed from running speed data, and a high-frequency camera (240 Hz) was used to study kinematic data. Paired samples t test and repeated-measures analysis of variance were conducted for each performance and kinematic variable, respectively. After the RST period, moderate to large improvements were observed for 0 to 20 m time, 0 to 30 m time, and 20 to 30 m time. All the repeated-sprint ability-related variables were significantly improved (P < .05). In addition, during fatigue conditions, a decrease in trunk flexion and kick-back mechanism and a reduced overstriding pattern was found after RST. The findings of this study suggest that incorporating RST may lead to improved sprint performance and promote a "safer" sprint pattern, particularly during periods of fatigue.
Erratum. Investigation of a Theoretical Model for the Rotational Shot Put Technique.
Journal of Applied Biomechanics
J Appl Biomech · 2025 Apr · PMID 39536741 · Publisher ↗
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The Effect of Scapular Orientation on Measures of Rotator Cuff Tendon Impingement: A Simulation Study.
Lawrence RL, Ivens R, Caldwell CA … +1 more , Harris-Hayes M
J Appl Biomech · 2024 Dec · PMID 39527948 · Full text
Mechanical impingement of the rotator cuff tendons against the acromion (subacromial) and glenoid (internal) during shoulder motions has long been thought to contribute to tears. Clinically, the risk for impingement is t...
Mechanical impingement of the rotator cuff tendons against the acromion (subacromial) and glenoid (internal) during shoulder motions has long been thought to contribute to tears. Clinically, the risk for impingement is thought to be influenced by scapular movement impairments. Therefore, our purpose was to determine the extent to which simulated changes in scapular orientation impact the proximity between the rotator cuff tendon footprint and the acromion and glenoid during scapular plane abduction. Specifically, shoulder kinematics were tracked in 25 participants using a high-speed biplane videoradiography system. Scapular movement impairments were simulated by rotating each participant's scapula from their in vivo orientation about the scapular axes (±2°, ±5°, and ±10°). Subacromial and internal proximities were described using minimum distances, proximity center locations, and prevalence of contact. Statistical parametric mapping was used to investigate the extent to which these measures were impacted by simulated changes in scapular orientation. Simulated changes in scapular orientation significantly altered proximity patterns in a complex manner that depended on the impingement mechanism, humerothoracic elevation angle, and magnitude of the simulated change. Clinicians should be mindful of these factors when interpreting the potential effects during a clinical examination.
Investigation of a Theoretical Model for the Rotational Shot Put Technique.
Kato T, Maeda K, Mizushima J … +1 more , Maeda A
J Appl Biomech · 2024 Nov · PMID 39504951 · Publisher ↗
The biomechanics of the rotational shot put technique have been demonstrated. However, the causal relationships among kinematics and kinetics for achieving higher release velocity remain poorly understood. This study inv...
The biomechanics of the rotational shot put technique have been demonstrated. However, the causal relationships among kinematics and kinetics for achieving higher release velocity remain poorly understood. This study investigated these causal relationships among biomechanical variables for achieving a higher release velocity in the rotational shot put technique. The study included 22 male shot putters whose 3-dimensional motion was captured during official competitions. Key kinematic and kinetic variables throughout the shot put motion were calculated, as suggested by previous studies. Path analysis was used to explore a hierarchical model that postulates both direct and indirect effects among variables. The findings revealed that the impulse of the shot, system angular momentum, and system linear momentum were critical kinetic variables contributing directly to release velocity. Additionally, 8 kinematic variables significantly affected the impulse of the shot, including shoulder rotation, shot path length, and trunk tilt, while movements such as swings and extensions of the lower extremities were related to system momentum. This model not only provides a detailed understanding of the mechanics involved in the rotational technique but also informs technical coaching strategies in the shot put.
Foot-Ankle Mechanical Transmission: Age Effects and the Relation to Ankle Push-Off During Walking.
Gray AJ, Takahashi KZ, Kashefsky HE … +1 more , Franz JR
J Appl Biomech · 2024 Dec · PMID 39500307 · Publisher ↗
Older adults walk with less push-off power than younger adults. Principally attributed to plantar flexor dysfunction, growing evidence implicates interactions between the foot and ankle as critical for generating effecti...
Older adults walk with less push-off power than younger adults. Principally attributed to plantar flexor dysfunction, growing evidence implicates interactions between the foot and ankle as critical for generating effective push-off. Our purposes were to measure age effects on foot-ankle mechanical transmission (FAMT, ie, the ratio between metatarsal phalangeal extension and medial gastrocnemius fascicle length change), and its association with ankle push-off during walking. We hypothesized that (1) FAMT would be lesser in older adults and (2) lesser FAMT would positively correlate with slower preferred speeds and reduced ankle push-off intensity. Fourteen younger adults (25 [6] y) and 15 older adults (71 [5] y) participated. Older adults had 45% to 48% lesser FAMT than younger adults from 0° to 30° metatarsal phalangeal extension-an age-related difference that was not evident from 30° to 60° metatarsal phalangeal extension. However, we did not find any significant correlations with walking outcomes. Assuming our findings can be replicated in future studies and represent a genuine phenomenon of relevance to the biomechanics of aging gait, we suspect that compensations may be discovered in older adults to explain this lack of significance. Future work should include measures of muscle activities and foot mechanics during walking and/or perform more controlled comparisons at fixed speeds.
Spring-Mass Characteristics in Runners Before and After a 56-km Road Ultramarathon.
Burns GT, Tam N, Langerak NG … +2 more , Zernicke RF, Lamberts RP
J Appl Biomech · 2024 Dec · PMID 39500304 · Publisher ↗
Ultramarathons are a unique model to study the effects of systemic fatigue in athletes. This investigation applied the spring-mass template to study runners before and 2 days after a road ultramarathon to characterize th...
Ultramarathons are a unique model to study the effects of systemic fatigue in athletes. This investigation applied the spring-mass template to study runners before and 2 days after a road ultramarathon to characterize the effects of fatigue on systemic gait patterns. Overground kinetics were captured 7 days before and 2 days after the event in 14 runners. Traditional kinetic and spring-mass parameters were calculated, along with nonlinear regression-derived parameters and spring-mass model fit metrics. After the ultramarathon, vertical force magnitudes and loading rates were unchanged, but impact peaks increased (1.88 ± 0.08-1.95 ± 0.10 bodyweight). Ground contact times were modestly shorter (-3 ± 1 ms), resulting in increased leg stiffness (10.0 ± 0.5-10.3 ± 0.5 kN/m) with equivocal vertical stiffnesses. The deviation from the modeled spring-mass kinetics also increased (171.3 ± 15.0-181.4 ± 16.5 N). Overall, the systemic mechanical behaviors of the runners persisted despite the fatigue and stress induced by a road ultramarathon. These findings support previous observations that runners maintain gross mechanical behavior when fatigued with small compensatory changes in spatiotemporal and traditional spring-mass characteristics. However, these findings also suggest that the variability within that gross behavior may increase after stress, suggesting new opportunities for quantifying those deviations.
A Potential Mechanism Involved in the Regularity of Center-of-Pressure Displacements During Achieving Unipedal Equilibrium on Stable and Unstable Surfaces.
Promsri A
J Appl Biomech · 2024 Dec · PMID 39496262 · Publisher ↗
Sample entropy (SampEn) is a widely used measure for estimating the regularity of center-of-pressure (COP) trajectories, with high COP regularity (low SampEn) commonly interpreted as ineffective postural control. The cur...
Sample entropy (SampEn) is a widely used measure for estimating the regularity of center-of-pressure (COP) trajectories, with high COP regularity (low SampEn) commonly interpreted as ineffective postural control. The current study aimed to investigate one possible source of COP regularity-agonist-antagonist coactivation-resulting in joint stiffness or action stability. A cross-correlation analysis was conducted to determine the similarity (coactivation) level of 5 pairs of lower limb agonist-antagonist electromyographic signals. SampEn was applied to anteroposterior (ap) and mediolateral (ml) COP displacements. Electromyographic and COP signals were simultaneously derived from 25 active young adults (25.6 ± 4.0 years) during unipedal balancing on stable and multiaxial-unstable surfaces. Then, the correlation between individual agonist-antagonist cross-correlation coefficients and SampEn-COP was explored. The results show that only the tibialis anterior-peroneus longus (TA-PL) coactivations are negatively correlated with SampEn-COPap/ml (P ≤ .030) in both surface conditions, with greater TA-PL coactivation appearing with lower SampEn-COPap/ml. In addition, sex effects as one factor that might influence postural control were also tested. Women exhibited greater TA-PL coactivation (P = .017) and lower SampEn-COPap (P = .005) than men. Together, TA-PL coactivation could be one possible origin of COP regularity, but its effects might be detrimental to unipedal postural control, especially for women.
Normative Extensor Hallucis Brevis Muscle Activity During Locomotion Following the Development of a Novel Ultrasound-Guided Fine-Wire Electromyography Protocol.
Robb KA, Sutherland K, Perry SD
J Appl Biomech · 2024 Dec · PMID 39481370 · Publisher ↗
Fine-wire electromyography (EMG) is a traditional laboratory technique to estimate muscle activity of the small foot muscles, however, recordings have not been reported from extensor hallucis brevis (EHB). As an extensor...
Fine-wire electromyography (EMG) is a traditional laboratory technique to estimate muscle activity of the small foot muscles, however, recordings have not been reported from extensor hallucis brevis (EHB). As an extensor of the great toe, EHB is an important muscle when studying physiological changes associated with foot pathologies such as hallux valgus. The purpose of this study was to develop an ultrasound-guided fine-wire EMG protocol to record EHB muscle activity and report normative EMG profiles of healthy young adults during locomotion. Sixteen asymptomatic young adults completed 20 walking trials at a self-selected velocity. Ensemble averages were calculated from the time normalized linear envelopes and represented from 0% to 100% of the single stance phase of gait. EHB muscle bursts were observed between 0% and 20% of the stance phase of gait in all participants. A second burst of EMG was observed between 80% and 100% of stance in 50% of the participants. This study introduces a novel ultrasound-guided EMG protocol and normative data from EHB recordings suggest a synergistic role to anterior compartment musculature at contact. These results provide preliminary insights into understanding the functional role of EHB and may help elucidate the biomechanical factors exacerbating the progression of hallux pathologies.
Effects of Changing Hip Position on Scapular Kinematics.
Schlittler SE, Suprak DN, Brilla LR … +1 more , San Juan JG
J Appl Biomech · 2024 Dec · PMID 39481365 · Publisher ↗
The effects of hip position and posture on scapular kinematics have yet to be explored. The purpose of this study was to measure differences in scapular kinematics with changing hip position. Scapular kinematics were mea...
The effects of hip position and posture on scapular kinematics have yet to be explored. The purpose of this study was to measure differences in scapular kinematics with changing hip position. Scapular kinematics were measured during scapular plane humeral elevation. Twenty-four subjects were required to elevate the dominant arm up to 120° in the following randomized conditions: standing, seated, seated ipsilateral hip flexion, and seated contralateral hip flexion. Two-way analyses of variance were used to evaluate effects of shoulder elevation and hip position on scapular upward rotation, posterior tilt (PT), and external rotation. For external rotation, there was no significant interaction (P = .714) and no main effect of elevation (P = .618) or condition (P = .390). For PT, there was no significant interaction (P = .693) but significant main effects of elevation (P < .001) and condition (P < .001), with the greatest PT in standing. For upward rotation, there was no significant interaction (P = .698), a significant main effect of elevation (P < .001), and no significant effect of condition (P = .726). The effect on PT may not be clinically significant. These results may serve as a baseline measurement of healthy scapular kinematics across hip positions.
Kinematic Sequence Differences Between Trained Baseball Players and Untrained Adolescent Individuals.
Wukelic C, Machak S, Gromeier M … +1 more , Shultz SP
J Appl Biomech · 2024 Dec · PMID 39442916 · Publisher ↗
An overhead throwing motion is a common gross motor skill often taught in early childhood to improve physical activity participation. Yet, research investigating motor efficiency in overhead throws often focuses on impro...
An overhead throwing motion is a common gross motor skill often taught in early childhood to improve physical activity participation. Yet, research investigating motor efficiency in overhead throws often focuses on improving performance in trained individuals. This project compares kinematic sequencing between trained and untrained youth. After a brief warm-up, untrained high school students (N = 9) and trained high school and college students (N = 10) threw a weighted tennis ball for accuracy (N = 10 throws). Upper extremity angular velocities were collected using 3-dimensional inertial sensor motion capture. Kinematic sequencing of joints and segments (pelvis, trunk, shoulder, elbow, and wrist) was assessed using Kruskal-Wallis test; Friedman and Wilcoxon tests identified group differences between sequences. Seven independent kinematic sequences were identified (N = 2 unique trained; N = 3 unique untrained; N = 2 shared). The rankings for the trained group maintained a mostly consistent pattern with only elbow and wrist joints producing similar rankings. The untrained group lacked that consistency with similar rankings of elbow versus wrist and shoulder versus elbow. Trained individuals threw with a more efficient proximal-to-distal sequencing pattern than the untrained participants, specifically at the trunk and shoulder. Continuous training of gross motor skills beyond initial skill development is necessary to maintain motor proficiency.
Do Experienced Adolescent Competition Dancers Alter Landing Kinematics and Kinetics for Split Leaps or Center Leaps After Fatigue?
Mink ZR, Esquivel A
J Appl Biomech · 2024 Dec · PMID 39348883 · Publisher ↗
Most injuries that dancers sustain are to the lower extremities, specifically the foot and ankle region. Numerous potential risk factors have been examined for dancer injuries such as technical mistakes and fatigue. The...
Most injuries that dancers sustain are to the lower extremities, specifically the foot and ankle region. Numerous potential risk factors have been examined for dancer injuries such as technical mistakes and fatigue. The purpose of this study was to compare landing kinematics and kinetics during jumps that are common in dance pre and postfatigue. Ten adolescent advanced level dancers participated in this study. Subjects completed 3 split leaps and 3 center leaps before and after a fatigue protocol performed on a stationary bike. Live motion capture was used to record landing kinematic and kinetic data. Results of this study showed a significant increase in ankle eversion and external rotation angles for center leaps from pre- to postfatigue protocol (P = .020 and P = .020, respectively) as well as significant increases in ankle eversion and knee adduction moments for center leaps (P = .020 and P = .036, respectively). These results show that after a fatigue protocol, there are changes to the kinematics of dancers that may make them more susceptible to ankle injury.
Effects of Stroboscopic Goggles on Standing Balance in the Spatiotemporal and Frequency Domains: An Exploratory Study.
McCreary ME, Lapish CM, Lewis NM … +3 more , Swearinger RD, Ferris DP, Pliner EM
J Appl Biomech · 2024 Dec · PMID 39313212 · Full text
Balance training paradigms have been shown to effectively reduce fall risk. Visual feedback is an important sensory mechanism for regulating postural control, promoting visual perturbations for balance training paradigms...
Balance training paradigms have been shown to effectively reduce fall risk. Visual feedback is an important sensory mechanism for regulating postural control, promoting visual perturbations for balance training paradigms. Stroboscopic goggles, which oscillate from transparent to opaque, are a form of visual perturbation, but their effect on standing balance has not been assessed. In this study, 29 participants stood in bilateral and tandem stances as the center of pressure was recorded for 6 consecutive minutes wherein there were no stroboscopic perturbations in the first and last minutes. Spatial-temporal, frequency domain, and nonlinear standing balance parameters were calculated for each period. More differences in spatial-temporal parameters due to the strobe were found in the medial-lateral direction than the anterior-posterior direction. More differences in frequency domain parameters were observed in the anterior-posterior direction than the medial-lateral direction, but this did not occur for each variable. The nonlinear parameters were strongly affected by the strobe. Stroboscopic perturbations did not affect the bilateral and tandem stances equally. Spatial-temporal parameters for the tandem stance were greater in magnitude during the strobe period than the no strobe periods. This effect was not seen with the bilateral stance. This indicates that the efficacy of stroboscopic perturbations for challenging standing balance depends on task difficulty. Balance training paradigms that utilize stroboscopic perturbations will need to harmonize these perturbations with task difficulty.
Relationship Between Supporting Leg Stiffness and Trunk Kinematics of the Kicking Leg During Soccer Kicking.
Tamura A, Shimura K, Inoue Y
J Appl Biomech · 2024 Dec · PMID 39293787 · Publisher ↗
The stiffness of the supporting leg may alter the energy transfer to the trunk and lower extremities of the kicking leg, which may affect kick performance. This study aimed to clarify whether the stiffness of the support...
The stiffness of the supporting leg may alter the energy transfer to the trunk and lower extremities of the kicking leg, which may affect kick performance. This study aimed to clarify whether the stiffness of the supporting leg affects the trunk kinematics during kicking and kicking performance in soccer players. Twenty-two male collegiate soccer players participated in the study. The data for the stiffness properties of the supporting leg and trunk kinematics were obtained and calculated using a 3-dimensional motion analysis system. The results showed that a greater leg stiffness of the supporting leg was associated with a lower trunk rotation angle during kicking. There were no significant correlations between the maximum swing speed and the stiffness of the supporting leg (P < .05). These results suggest that stiffness of the supporting leg may restrain trunk rotation during the kicking motion. However, the lack of a relationship with swing speed indicates the need for further investigation into its effects on kicking performance.
The Effects of Running Foot Strike Manipulation on Pelvic Floor Muscle Activity in Healthy Nulliparous Females.
Steimling M, Steimling M, Malloy P … +1 more , Madara K
J Appl Biomech · 2024 Oct · PMID 39244190 · Publisher ↗
Vertical loading rate (VLR) and pelvic floor muscle activity (PFA) increase with running velocity, which may indicate a relationship between VLR and PFA. Foot strike pattern has been shown to influence VLR while running,...
Vertical loading rate (VLR) and pelvic floor muscle activity (PFA) increase with running velocity, which may indicate a relationship between VLR and PFA. Foot strike pattern has been shown to influence VLR while running, but little is known about its influence on PFA. Twenty healthy women ran on a treadmill for 2 conditions: with a rearfoot strike and with a forefoot strike. PFA was measured with electromyography. Running kinematics associated with VLR were collected using inertial measurement units and tibial accelerometers. Change scores between conditions were calculated for average PFA and running kinematics: peak vertical tibial acceleration, vertical excursion of the center of mass (VO), and cadence. Paired t tests assessed differences between running conditions for all variables. Pearson correlations assessed the relationships between changes in PFA and running kinematics. PFA was significantly higher during the forefoot compared with the rearfoot strike condition. Change in vertical tibial acceleration was positively correlated with change in PFA during the right stance. Change in cadence was negatively correlated, and change in vertical excursion of the center of mass was positively correlated with change in PFA during left stance. The average PFA increased during the forefoot strike pattern condition. Changes in PFA were correlated with changes in running kinematics associated with VLR.
Fatigue-Related Changes in Running Technique and Mechanical Variables After a Maximal Incremental Test in Recreational Runners.
Borba EF, Silva ESD, Alves LL … +7 more , Neto ARDS, Inda AR, Ibrahim BM, Ribas LR, Correale L, Peyré-Tartaruga LA, Tartaruga MP
J Appl Biomech · 2024 Oct · PMID 39231490 · Publisher ↗
Understanding the changes in running mechanics caused by fatigue is essential to assess its impact on athletic performance. Changes in running biomechanics after constant speed conditions are well documented, but the ada...
Understanding the changes in running mechanics caused by fatigue is essential to assess its impact on athletic performance. Changes in running biomechanics after constant speed conditions are well documented, but the adaptive responses after a maximal incremental test are unknown. We compared the spatiotemporal, joint kinematics, elastic mechanism, and external work parameters before and after a maximal incremental treadmill test. Eighteen recreational runners performed 2-minute runs at 8 km·h-1 before and after a maximal incremental test on a treadmill. Kinematics, elastic parameters, and external work were determined using the OpenCap and OpenSim software. We did not find differences in spatiotemporal parameters and elastic parameters (mechanical work, ankle, and knee motion range) between premaximal and postmaximal test conditions. After the maximal test, the runners flexed their hips more at contact time (19.4°-20.6°, P = .013) and presented a larger range of pelvis rotation at the frontal plane (10.3°-11.4°, P = .002). The fatigue applied in the test directly affects pelvic movements; however, it does not change the lower limb motion or the spatiotemporal and mechanical work parameters in recreational runners. A larger frontal plane motion of the pelvis deserves attention due to biomechanical risk factors associated with injuries.
Validation of Linear and Nonlinear Gait Variability Measures Derived From a Smartphone System Compared to a Gold-Standard Footswitch System During Overground Walking.
Di Bacco VE, Gage WH
J Appl Biomech · 2024 Oct · PMID 39222917 · Publisher ↗
Smartphones, with embedded accelerometers, may be a viable method to monitor gait variability in the free-living environment. However, measurements estimated using smartphones must first be compared to known quantities t...
Smartphones, with embedded accelerometers, may be a viable method to monitor gait variability in the free-living environment. However, measurements estimated using smartphones must first be compared to known quantities to ensure validity. This study assessed the validity and reliability of smartphone-derived gait measures compared to a gold-standard footswitch system during overground walking. Seventeen adults completed three 8-minute overground walking trials during 3 separate visits. The stride time series was calculated as the time difference between consecutive right heel contact events within the footswitch and smartphone-accelerometry signals. Linear (average stride time, stride time standard deviation, and stride time coefficient of variation) and nonlinear (fractal scaling index, approximate entropy, and sample entropy) measures were calculated for each stride time series. Bland-Altman plots with 95% limits of agreement assessed agreement between systems. Intraclass correlation coefficients assessed reliability across visits. Bland-Altman plots revealed acceptable limits of agreement for all measures. Intraclass correlation coefficients revealed good-to-excellent reliability for both systems, except for fractal scaling index, which was moderate. The smartphone system is a valid method and performs similarly to gold-standard research equipment. These findings suggest the development and implementation of an inexpensive, easy-to-use, and ubiquitous telehealth instrument that may replace traditional laboratory equipment for use in the free-living environment.
Concussion History Moderates Trunk Motion and Lower Extremity Biomechanical Relationships During Jump Landing and Cutting.
Kowalczyk KM, Shumski EJ, Schmidt JD … +1 more , Lynall RC
J Appl Biomech · 2024 Oct · PMID 39214517 · Publisher ↗
Concussion history, trunk motion, and lower extremity biomechanics associate with musculoskeletal injury risk. We aimed to examine the interaction between concussion history and trunk motion as possible modifiable factor...
Concussion history, trunk motion, and lower extremity biomechanics associate with musculoskeletal injury risk. We aimed to examine the interaction between concussion history and trunk motion as possible modifiable factors for injury risk biomechanics during jump landing and cutting. Division I female athletes (24 with, 20 without concussion history) performed jump landings and jump-to-cuts at 45° in the opposite direction of the landing limb. We used multiple linear regressions with interaction terms to examine ankle dorsiflexion angle, knee flexion and abduction angle, and external knee flexion and abduction moment. We observed a group by trunk flexion interaction for nondominant external knee flexion moment (P = .042) during jump landing. Concussion history associated with increased external knee flexion moment as trunk flexion increased. We observed a group by trunk flexion interaction for the dominant limb dorsiflexion angle (P = .044), and group by trunk lateral bending interactions for the dominant (P = .039) and nondominant limb (P = .016) external knee flexion moment during cutting. During cutting, concussion history associated with decreased dominant dorsiflexion angles as trunk flexion increased, and decreased dominant and nondominant external knee flexion moment as lateral bending toward the planted limb increased. Concussion history associated with atypical biomechanics as trunk flexion and lateral bending increased.
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