Journal of Applied Biomechanics最新文献

The upper body and trunk muscles are crucial to perform soccer kicks. Resistance training targeting these muscles may modify the pattern adopted during kicking. This study aimed to investigate the effect of resistance training of the arm and anterior trunk muscles on instep kicking kinematics. Twenty-six male participants were randomly allocated into a training group or control group. The training group underwent resistance training of arm and trunk muscles and practiced the instep kick for 8 weeks. The control group only practiced kicking during the same period. The trunk, hip, and knee kinematics were assessed during the instep kick before and after the intervention. Kinematics were analyzed according to their data distribution with statistical parametric or nonparametric mapping. The effect of the training on the 1-repetition maximum test was analyzed using a repeated-measures multivariate analysis of variance. The training group showed greater hip extension after the training during the backswing phase (Hedge g effect size of 0.316-0.321) and increased 1-repetition maximum for all exercises. There were no other differences. The present study documented the nonlocal effect of strengthening training in which arm and trunk muscle training resulted in changes in hip kinematics during the backswing phase of the instep kick.

Breast cancer affects one in 8 females with a 5-year survival rate of 89%. Up to 72% of breast cancer survivors have trouble with activities of daily living (ADL) following treatment. Increased time-from-treatment improves some measures of function, yet ADL limitations persist. Therefore, this study assessed the effect of time-from-treatment on upper extremity kinematics during ADLs in breast cancer survivors. Twenty-nine female breast cancer survivors were divided into 2 groups: <1 year (n = 12) and 1-2 years (n = 17) from treatment. Kinematics were collected during 6 ADL tasks, and humerothoracic joint angles were quantified. A 2-way mixed analysis of variance assessed the effects of time-from-treatment and arm on maximum angles for each ADL. Decreased maximum angle existed for breast cancer survivors with increased time-from-treatment during all ADLs. Breast cancer survivors in the 1-2 years group used ∼28° to 32° lower elevation, ∼14° to 28° lower axial rotation, and ∼10° to 14° lower plane of elevation range across tasks. Decreased ranges of arm movement during ADLs with increased time-from-treatment may reflect compensatory movement strategies. Recognizing this shift in strategies and accompanying underlying disease progression can help inform responses to functional performance limitations in breast cancer survivors as delayed effects are present posttreatment.

Single-leg landings with or without subsequent jumping are frequently used to evaluate landing biomechanics. The purpose of this study was to investigate the effects of subsequent jumping on the external knee abduction moment and trunk and hip biomechanics during single-leg landing. Thirty young adult female participants performed a single-leg drop vertical jumping (SDVJ; landing with subsequent jumping) and single-leg drop landing (SDL; landing without subsequent jumping). Trunk, hip, and knee biomechanics were evaluated using a 3-dimensional motion analysis system. The peak knee abduction moment was significantly larger during SDVJ than during SDL (SDVJ 0.08 [0.10] N·m·kg-1·m-1, SDL 0.05 [0.10] N·m·kg-1·m-1, P = .002). The trunk lateral tilt and rotation angles toward the support-leg side and external hip abduction moment were significantly larger during SDVJ than during SDL (P < .05). The difference in the peak hip abduction moment between SDVJ and SDL predicted the difference in the peak knee abduction moment (P = .003, R2 = .252). Landing tasks with subsequent jumping would have advantages for evaluating trunk and hip control as well as knee abduction moment. In particular, evaluating hip abduction moment may be important because of its association with the knee abduction moment.

Inertial sensors may help clinicians to assess patients' movement and potentially support clinical decision making. Our aim was to determine whether shoulder range of motion during movement tasks measured using inertial sensors is capable of accurately discriminating between patients with different shoulder problems. Inertial sensors were used to measure 3-dimensional shoulder motion during 6 tasks of 37 patients on the waiting list for shoulder surgery. Discriminant function analysis was used to identify whether the range of motion of different tasks could classify patients with different shoulder problems. The discriminant function analysis could correctly classify 91.9% of patients into one of the 3 diagnostic groups based. The tasks that associated a patient with a particular diagnostic group were the following: subacromial decompression: abduction, rotator cuff repair of tears ≤5 cm: flexion and rotator cuff repair of tears >5 cm: combing hair, abduction, and horizontal abduction-adduction. The discriminant function analysis showed that range of motion measured by inertial sensors can correctly classify patients and could be used as a screening tool to support surgery planning.

Soccer, one of the most popular sports in the world, has one of the highest rates of sports-related concussions. Additionally, soccer players are frequently exposed to nonconcussive impacts from intentionally heading the ball, a fundamental component of the sport. There have been many studies on head impact exposure in soccer, but few focus on soccer practices or practice activities. This study aimed to characterize the frequency and magnitude of head impacts in National Collegiate Athletic Association Division I female soccer practice activities using a custom-fit instrumented mouthpiece. Sixteen players were instrumented over the course of 54 practice sessions. Video analysis was performed to verify all mouthpiece-recorded events and classify practice activities. Category groupings of practice activities include technical training, team interaction, set pieces, position-specific, and other. Differences in head impact rates and peak resultant kinematics were observed across activity types and category groupings. Technical training had the highest impact rate compared to other category groupings. Impacts occurring during set piece activities had the highest mean kinematic values. Understanding drill exposure can help inform coaches on training plans aimed to reduce head impact exposure for their athletes.

There are relatively few running studies that have attempted to prospectively identify biomechanical risk factors associated with Achilles tendon (AT) injuries. Therefore, the aim was to prospectively determine potential running biomechanical risk factors associated with the development of AT injuries in recreational, healthy runners. At study entry, 108 participants completed a set of questionnaires. They underwent an analysis of their running biomechanics at self-selected running speed. The incidence of AT running-related injuries (RRI) was assessed after 1-year using a weekly questionnaire standardized for RRI. Potential biomechanical risk factors for the development of AT RRI injury were identified using multivariable logistic regression. Of the 103 participants, 25% of the sample (15 males and 11 females) reported an AT RRI on the right lower limb during the 1-year evaluation period. A more flexed knee at initial contact (odds ratio = 1.146, P = .034) and at the midstance phase (odds ratio = 1.143, P = .037) were significant predictors for developing AT RRI. The results suggested that a 1-degree increase in knee flexion at initial contact and midstance was associated with a 15% increase in the risk of an AT RRI, thus causing a limitation of training or a stoppage of running in runners.

In this review, we elaborate on how musculoskeletal (MSK) modeling combined with dynamic movement simulation is gradually evolving from a research tool to a promising in silico tool to assist medical doctors and physical therapists in decision making by providing parameters relating to dynamic MSK function and loading. This review primarily focuses on our own and related work to illustrate the framework and the interpretation of MSK model-based parameters in patients with 3 different conditions, that is, degenerative joint disease, cerebral palsy, and adult spinal deformities. By selecting these 3 clinical applications, we also aim to demonstrate the differing levels of clinical readiness of the different simulation frameworks introducing in silico model-based biomarkers of motor function to inform MSK rehabilitation and treatment, with the application for adult spinal deformities being the most recent of the 3. Based on these applications, barriers to clinical integration and positioning of these in silico technologies within standard clinical practice are discussed in the light of specific challenges related to model assumptions, required level of complexity and personalization, and clinical implementation.

In sports situations, players may be required to throw at different speeds. The question of how skilled players throw the ball accurately to the desired location under different speed conditions is of interest to biomechanics researchers. Previous research suggested that throwers use different types of joint coordination. However, joint coordination with a change in throwing speed has not been studied. Here, we show the effects of changes in throwing speed on joint coordination during accurate overhead throwing. Participants were seated on a low chair with their trunk fixed and threw a baseball aimed at a target under 2 different speed conditions (slow and fast). In the slow condition, the elbow flexion/extension angle coordinated with other joint angles and angular velocities to reduce the variability of the vertical hand velocity. In the fast condition, the shoulder internal/external rotation angle and the shoulder horizontal flexion/extension angular velocity coordinated with other joint angles and angular velocities to reduce the variability of the vertical hand velocity. These results showed that joint coordination differed with changes in throwing speed, indicating that joint coordination is not always fixed, but may differ depending on the task constraints, such as throwing speed.

Inertial measurement units (IMUs) attached to the distal tibia are a validated method of measuring lower-extremity impact accelerations, called tibial accelerations (TAs), in runners. However, no studies have investigated the effects of small errors in IMU placement, which would be expected in real-world, autonomous use of IMUs. The purpose of this study was to evaluate the effect of a small proximal shift in IMU location on mean TAs and relationships between TAs and ground reaction force loading rates. IMUs were strapped to 18 injury-free runners at a specified standard location (∼1 cm proximal to medial malleolus) and 2 cm proximal to the standard location. TAs and ground reaction forces were measured while participants ran at self-selected and 10% slower/faster speeds. Mean TA was lower at the standard versus proximal IMU location in the faster running condition (P = .026), but similar in the slower (P = .643) and self-selected conditions (P = .654). Mean TAs measured at the standard IMU explained more variation in ground reaction force loading rates (r2 = .79-.90; P < .001) compared with those measured at the proximal IMU (r2 = .65-.72; P < .001). These results suggest that careful attention should be given to IMU placement when measuring TAs during running.

A systematic search was performed of online databases for any anterior cruciate ligament (ACL) injuries within the NBA. Video was obtained of injuries occurring during competition and downloaded for 2-dimensional video analysis. Thirty-five in-game videos were obtained for analysis. Of the reviewed cases, 19% were noncontact ACL injuries where there was no player-to-player contact from an opposing player. Three injury mechanism categories were found based on the events at the point of initial ground contact of the foot of the injured limb: single-leg casting (mean dorsiflexion angle 18.9° (14.4°); mean knee flexion angle 15.6° (7.8°); and mean trunk lateral flexion 18.2° (8.4°)); bilateral hop (mean dorsiflexion angle 18.2° (15.2°), mean knee flexion angle 21° (14.5°), mean trunk extension angle 6.9° (11.4°), and landing angle from the athlete's center of mass 47.9° (10.1°)); and single-leg landing after contact (mean abduction angle of the swing leg 105.4° (18.1°), mean knee flexion angle of the injured limb 34.2° (8.0°), and mean trunk ipsilateral flexion angle 22.2° (7.0°)).