Differences In Joint Kinetics Research Articles

Injury and performance related biomechanical differences between recreational and collegiate runners.

Running related injuries (RRI) are common, but factors contributing to running performance and RRIs are not commonly compared between different types of runners. We compared running biomechanics previously linked to RRIs and performance between 27 recreational and 35 collegiate runners. Participants completed 5 overground running trials with their dominant limb striking a force plate, while outfitted with standardised footwear and 3-dimensional motion capture markers. Post hoc comparisons revealed recreational runners had a larger vertical loading rate (194.5 vs. 111.5 BW/s, p < 0.001) and shank angle (6.80 vs. 2.09, p < 0.001) compared with the collegiate runners who demonstrated greater vertical impulse (0.349 vs. 0.233 BWs, p < 0.001), negative impulse (-0.022 vs. -0.013 BWs, p < 0.001), positive impulse (0.024 vs. 0.014 BWs, p < 0.001), and propulsive force (0.390 vs. 0.333 BW, p = 0.002). Adjusted for speed, collegiate runners demonstrated greater total support moment (TSM), plantar flexor moment, knee extensor moment, hip extensor moment, and had greater proportional plantar flexor moment contribution and less knee extensor moment contribution to the TSM compared with recreational runners. Unadjusted for speed, collegiate runners compared with recreational had greater TSM and plantar flexor moment but similar joint contributions to the TSM. Greater ankle joint contribution may be more efficient and allow for greater capacity to increase speed. Improving plantarflexor function during running provides a strategy to improve running speed among recreational runners. Moreover, differences in joint kinetics and ground reaction force characteristics suggests that recreational and collegiate runners may experience different types of RRI.

Knee kinetics and the medial femoral cartilage cross-sectional area response to loading in indviduals with anterior cruciate ligament reconstruction

BackgroundUltrasonography is capable of detecting morphological changes in femoral articular cartilage cross-sectional area in response to an acute bout of walking; yet, the response of femoral cartilage cross-sectional area varies between individuals. It is hypothesized that differences in joint kinetics may influence the response of cartilage to a standardized walking protocol. Therefore, the study purpose was to compare internal knee abduction and extension moments between individuals with anterior cruciate ligament reconstruction who demonstrate an acute increase, decrease, or unchanged medial femoral cross-sectional area response following 3000 steps. MethodsThe medial femoral cartilage in the anterior cruciate ligament reconstructed limb was assessed with ultrasonography before and immediately following 3000 steps of treadmill walking. Knee joint moments were calculated in the anterior cruciate ligament reconstructed limb and compared between groups throughout the stance phase of gait using linear regression and functional, mixed effects waveform analyses. FindingsNo associations between peak knee joint moments and the cross-sectional area response were observed. The group that demonstrated an acute cross-sectional area increase exhibited 1) lower knee abduction moments in early stance in comparison to the group that exhibited a decreased cross-sectional area response; and 2) greater knee extension moments in early stance in comparison to the group with an unchanged cross-sectional area response. InterpretationThe propensity of femoral cartilage to acutely increase cross-sectional area in response to walking is consistent with less-dynamic knee abduction and knee extension moment profiles.

The influence of modeling parameters for computing joint kinetics in adolescent and adult pitchers

ABSTRACT Baseball pitching is a well-studied area of sports biomechanics partially due to high upper extremity (UE) injury rates. Joint kinetics have not been linked directly to UE injury in pitchers but are often used in lieu of injury data as a proxy for injury risk. Pitchers exhibit adaptations in the throwing arm that may affect body segment inertial parameters (BSIPs); however, these are unaccounted for in traditional modelling methods and may contribute to the lack of evidence linking joint kinetics to injury. Therefore, this study aimed to describe the BSIPs of the throwing arm in adolescent and adult pitchers and compare joint kinetics computed from traditional modelling methods to those using individualised BSIPs. Forty-five pitchers underwent dual-energy X-ray absorptiometry (DXA) scans and motion capture sessions in a biomechanics laboratory. Individual BSIPs from the DXA scans were used to estimate UE joint kinetics via inverse dynamics and compared to joint kinetics computed from scaled BSIPs. Throwing arm BSIPs in pitchers were significantly different from studies of the general population. Variable levels of agreement and significant differences in joint kinetics existed between methods, indicating that using joint kinetics computed via scaled models to identify pitchers at risk of injury may be inappropriate.

Lower Limb Joint Kinetics During Walking in Middle-Aged Runners With Low or High Lifetime Running Exposure.

Aging is associated with a distal-to-proximal shift in joint kinetics during walking. This plasticity of gait is amplified rather than attenuated in old adults with high physical capacity. Because running is associated with greater kinetic demands at the ankle, older individuals with more versus less lifetime running exposure may retain a larger proportion of their ankle kinetics. The purpose of the study was to compare lower-extremity joint kinetics during walking between middle-aged runners with high and low lifetime running exposure. Eighteen middle-aged runners (9 per group) participated. Joint kinetics were calculated from kinematic and ground reaction force data during overground walking at 1.3m·s-1 and compared between groups. High exposure runners produced 50% greater positive hip work (P = .03; Cohen d = 1.02) during walking compared with low exposure runners, but ankle kinetics were not different between groups. No other differences in joint kinetics or kinematics were observed between groups. These findings suggest that the age-related increase in hip joint kinetics during walking could be a compensatory gait strategy that is not attenuated by lifetime running exposure alone. Finally, the amount of lifetime running exposure did not affect ankle kinetics during walking in middle-aged runners.

Baseball Pitching Biomechanics Shortly After Ulnar Collateral Ligament Repair.

Background:The probability of returning to competition for injured baseball pitchers is similar after ulnar collateral ligament (UCL) repair as after UCL reconstruction, but the time to return is significantly quicker after UCL repair. Previous research has found no differences in pitching biomechanics between pitchers with and without a history of UCL reconstruction, but pitching biomechanics after UCL repair has not been studied.Hypothesis:There will be significant differences in pitching biomechanics between pitchers returning to play after UCL repair and pitchers with no injury history.Study Design:Controlled laboratory study.Methods:A total of 33 pitchers were tested shortly after UCL repair (9.8 ± 2.6 months) and compared with a matched group of 33 uninjured pitchers. Each group comprised 14 college pitchers and 19 high school pitchers. Shoulder and elbow passive ranges of motion were measured. The biomechanics of 10 fastballs was then collected using a 12-camera automated motion capture system. Ball velocity was measured using a separate 3-camera optical tracking system. Data were compared between the UCL repair group and the control group using the Student t test (significance set at P < .05).Results:There were no differences in passive range of motion or fastball velocity between the 2 groups. There were no differences in joint kinetics during pitching, but 3 kinematic variables showed significant differences. Specifically, the UCL repair group produced less elbow extension (flexion: 27° ± 6° vs 24° ± 4°, respectively; P = .03), less elbow extension velocity (2442 ± 367 vs 2631 ± 292 deg/s, respectively; P = .02), and less shoulder internal rotation velocity (6273 ± 1093 vs 6771 ± 914 deg/s, respectively; P = .049 ) compared with the control group.Conclusion:Elbow extension, elbow velocity, and shoulder velocity differed between pitchers with a recent history of UCL repair and a matched control group, but it is unclear whether this has clinical significance, as there were no differences in ball velocity and passive range of motion. Furthermore, it is unknown whether these few differences in pitching biomechanics resolve with time.Clinical Relevance:Elbow and shoulder kinematics during pitching might not be completely regained within the first year after UCL repair, although passive range of motion and pitch velocity show no difference in comparison to other healthy pitchers.

Abnormal Joint Moment Distributions and Functional Performance During Sit-to-Stand in Femoroacetabular Impingement Patients

BackgroundFemoroacetabular impingement (FAI) is a morphological abnormality of the hip joint that causes pain when performing a mechanically demanding activity of daily living such as the sit-to-stand (STS) task. Previous studies have assessed lower extremity joint mechanics during an STS task in various pathologies, yet the STS task has not been studied in FAI patients. ObjectiveThe objective of this study was to identify differences in joint kinetics and performance between FAI patients and healthy controls during a STS task. It was hypothesized that FAI patients would exhibit altered time needed to complete the STS task, as well as altered lower extremity biomechanics, when compared to healthy controls. DesignThis was a cross-sectional cohort study. SettingThe study took place at a motion capture laboratory at an institutional orthopedic facility. ParticipantsBiomechanical analysis was performed in 17 FAI patients and 31 age- and body mass index (BMI)−matched healthy controls during the STS task. MethodsSagittal plane joint moments, total support moment (TSM), joint contributions to the TSM, and functional measures during the STS task were compared between groups. Main Outcome MeasurementsPeak joint moments, TSM and joint contributions to the TSM were assessed during the STS task. In addition, the time to and value of the peak vertical ground reaction force (vGRF), limb symmetry index at peak vGRF, loading rate, and total time needed to perform the STS task were determined. ResultsCompared to the control participants, the FAI patients exhibited worse Hip Disability and Osteoarthritis Outcome Score (HOOS) pain and function subscores. No group differences were observed in peak sagittal joint moments during the STS task. However, when compared to controls, the FAI patients demonstrated reduced knee joint contributions to the TSM. In addition, the FAI patients exhibited increased time needed to perform the STS task, increased time to reach peak vGRF, and reduced lower extremity loading rate during the STS task. ConclusionsFAI patients demonstrated abnormal joint contributions to TSM and altered functional performance during the STS task. These altered movement patterns during the STS task may be compensatory mechanisms used by the FAI patients to reduce pain and to improve function. Level of EvidenceNot applicable.

Effects of age and step length on joint kinetics during stepping task

Following a balance perturbation, a stepping response is commonly used to regain support, and the distance of the recovery step can vary. To date, no other studies have examined joint kinetics in young and old adults during increasing step distances, when participants are required to bring their rear foot forward. Therefore, the purpose of this study was to examine age-related differences in joint kinetics with increasing step distance. Twenty young and 20 old adults completed the study. Participants completed a step starting from double support, at an initial distance equal to the individual's average step length. The distance was increased by 10% body height until an unsuccessful attempt. A one-way, repeated measures ANOVA was used to determine the effects of age on joint kinetics during the maximum step distance. A two-way, repeated measures, mixed model ANOVA was used to determine the effects of age, step distance, and their interaction on joint kinetics during the first three step distances for all participants. Young adults completed a significantly longer step than old adults. During the maximum step, in general, kinetic measures were greater in the young than in the old. As step distance increased, all but one kinetic measure increased for both young and old adults. This study has shown the ability to discriminate between young and old adults, and could potentially be used in the future to distinguish between fallers and non-fallers.

Oscillation and Reaction Board Techniques for Estimating Inertial Properties of a Below-knee Prosthesis

The purpose of this study was two-fold: 1) demonstrate a technique that can be used to directly estimate the inertial properties of a below-knee prosthesis, and 2) contrast the effects of the proposed technique and that of using intact limb inertial properties on joint kinetic estimates during walking in unilateral, transtibial amputees. An oscillation and reaction board system was validated and shown to be reliable when measuring inertial properties of known geometrical solids. When direct measurements of inertial properties of the prosthesis were used in inverse dynamics modeling of the lower extremity compared with inertial estimates based on an intact shank and foot, joint kinetics at the hip and knee were significantly lower during the swing phase of walking. Differences in joint kinetics during stance, however, were smaller than those observed during swing. Therefore, researchers focusing on the swing phase of walking should consider the impact of prosthesis inertia property estimates on study outcomes. For stance, either one of the two inertial models investigated in our study would likely lead to similar outcomes with an inverse dynamics assessment.

Oscillation and reaction board techniques for estimating inertial properties of a below-knee prosthesis.

The purpose of this study was two-fold: 1) demonstrate a technique that can be used to directly estimate the inertial properties of a below-knee prosthesis, and 2) contrast the effects of the proposed technique and that of using intact limb inertial properties on joint kinetic estimates during walking in unilateral, transtibial amputees. An oscillation and reaction board system was validated and shown to be reliable when measuring inertial properties of known geometrical solids. When direct measurements of inertial properties of the prosthesis were used in inverse dynamics modeling of the lower extremity compared with inertial estimates based on an intact shank and foot, joint kinetics at the hip and knee were significantly lower during the swing phase of walking. Differences in joint kinetics during stance, however, were smaller than those observed during swing. Therefore, researchers focusing on the swing phase of walking should consider the impact of prosthesis inertia property estimates on study outcomes. For stance, either one of the two inertial models investigated in our study would likely lead to similar outcomes with an inverse dynamics assessment.

Kinematic and Kinetic Evaluation of the Stance Phase of Stair Ambulation in Persons with Stroke and Healthy Adults: A Pilot Study

This study describes and contrasts the kinematics and kinetics of stair ambulation in people with chronic stroke and healthy control subjects. Three-dimensional motion data were collected from 10 persons with stroke (7 males) and 10 sex and age-matched older adults as they ascended and descended an instrumented staircase at self-selected speed with and without a handrail. Ankle, knee and hip joint angle and moment profiles were generated during stance and range of motion and peak moments were contrasted between groups, sides (stroke only) and condition. Cadence was lower in stroke than controls, although the kinematic profiles appeared similar during ascent and decent. Notable differences in joint kinetics were evident as the peak extensor moments were typically lower on the affected side in stroke compared with controls and the less affected side. These differences accounted for the lower magnitude net extensor support moment. The lower affected side hip abductor moments likely limited lateral stability. Handrail use tended to reduce the peak moments on the affected side only leading to more side-to-side differences than occurred without the handrail. The findings reveal differences in task performance between stroke and healthy groups that help inform rehabilitation practice.

Systematic Variation of Prosthetic Foot Spring Affects Center-of-Mass Mechanics and Metabolic Cost During Walking

Lower-limb amputees expend more energy to walk than non-amputees and have an elevated risk of secondary disabilities. Insufficient push-off by the prosthetic foot may be a contributing factor. We aimed to systematically study the effect of prosthetic foot mechanics on gait, to gain insight into fundamental prosthetic design principles. We varied a single parameter in isolation, the energy-storing spring in a prototype prosthetic foot, the controlled energy storage and return (CESR) foot, and observed the effect on gait. Subjects walked on the CESR foot with three different springs. We performed parallel studies on amputees and on non-amputees wearing prosthetic simulators. In both groups, spring characteristics similarly affected ankle and body center-of-mass (COM) mechanics and metabolic cost. Softer springs led to greater energy storage, energy return, and prosthetic limb COM push-off work. But metabolic energy expenditure was lowest with a spring of intermediate stiffness, suggesting biomechanical disadvantages to the softest spring despite its greater push-off. Disadvantages of the softest spring may include excessive heel displacements and COM collision losses. We also observed some differences in joint kinetics between amputees and non-amputees walking on the prototype foot. During prosthetic push-off, amputees exhibited reduced energy transfer from the prosthesis to the COM along with increased hip work, perhaps due to greater energy dissipation at the knee. Nevertheless, the results indicate that spring compliance can contribute to push-off, but with biomechanical trade-offs that limit the degree to which greater push-off might improve walking economy.

Kinetics and kinematics analysis of incremental cycling to exhaustion

Technique changes in cyclists are not well described during exhaustive exercise. Therefore the aim of the present study was to analyze pedaling technique during an incremental cycling test to exhaustion. Eleven cyclists performed an incremental cycling test to exhaustion. Pedal force and joint kinematics were acquired during the last three stages of the test (75%, 90% and 100% of the maximal power output). Inverse dynamics was conducted to calculate the net joint moments at the hip, knee and ankle joints. Knee joint had an increased contribution to the total net joint moments with the increase of workload (5–8% increase, p < 0.01). Total average absolute joint moment and knee joint moment increased during the test (25% and 39%, for p < 0.01, respectively). Increases in plantar flexor moment (32%, p < 0.01), knee (54%, p < 0.01) and hip flexor moments (42%, p = 0.02) were found. Higher dorsiflexion (2%, for p = 0.03) and increased range of motion (19%, for p = 0.02) were observed for the ankle joint. The hip joint had an increased flexion angle (2%, for p < 0.01) and a reduced range of motion (3%, for p = 0.04) with the increase of workload. Differences in joint kinetics and kinematics indicate that pedaling technique was affected by the combined fatigue and workload effects.

Differences in gait parameters between healthy subjects and persons with moderate and severe knee osteoarthritis: A result of altered walking speed?

Background While knee osteoarthritis has been shown to affect a multitude of kinematic, kinetic and temporo-spatial gait parameters, few investigations have examined the effect of increasing levels of radiographic osteoarthritis severity on these gait parameters. Fewer still have investigated the effect of walking speed on gait variables in persons with knee osteoarthritis. The objective of this study was to investigate the influence of walking speed on biomechanical variables associated with joint loading in persons with varying severities of medial compartment knee osteoarthritis. Methods Twenty-one persons with moderate osteoarthritis (Kellgren–Lawrence score 2–3) and 13 persons with severe osteoarthritis (Kellgren–Lawrence score of 4) participated. Twenty-two persons without knee pain or radiographic evidence of arthritis comprised a healthy control group. Sagittal plane kinetics, knee adduction moment, sagittal plane knee excursion, ground reaction forces and knee joint reaction forces were calculated from three-dimensional motion analysis at 1.0 m/s, self-selected and fastest tolerable walking speeds. Differences were analyzed using multivariate analysis of variance and multivariate analysis of covariance with speed as a covariate. Findings Persons with knee osteoarthritis showed significantly lower knee and ankle joint moments, ground reaction forces, knee reaction force and knee excursion when walking at freely chosen speeds. When differences in walking speed were accounted for in the analysis, the only difference found at all conditions was decreased knee joint excursion. Interpretation Compared to a healthy control group, persons with knee OA demonstrate differences in joint kinetics and kinematics. Except for knee excursion, these differences in gait parameters appear to be a result of slower freely chosen walking speeds rather than a result of disease progression.

Biomechanical Comparison of the Fastball from Wind-up and the Fastball from Stretch in Professional Baseball Pitchers

Background It has long been thought by many baseball coaches and players that throwing the fastball from the stretch is more stressful to the shoulder and elbow than throwing the fastball from the wind-up. However, no research has compared the biomechanics of these 2 pitch variations. Hypothesis There are differences in shoulder and elbow kinetics, kinematic position at front-foot contact, timing, and ball velocity between the 2 pitching variations. Study Design Controlled laboratory study. Methods Twenty-eight professional baseball pitchers (aged 22.1 ± 2.8 years) pitched fastballs from both the wind-up and stretch positions in an indoor laboratory setting. Three-dimensional motion-analysis systems were employed to capture the pitching motion. Kinetic variables, kinematic variables at lead-foot contact, and temporal variables of the 2 pitching variations were compared. Results There was no significant difference between the 2 pitch variations for the kinetic, kinematic, or temporal variables. The difference between the ball velocities was statistically significant, but the mean difference was only 0.2 m/s. Conclusions The pitching biomechanics between the wind-up and stretch fastball showed no statistical differences in joint kinetics, kinematics, or timing, and clinically insignificant differences in ball velocity. Clinical Relevance The current results suggest that pitching the fastball from the stretch is not necessarily more stressful to the shoulder and elbow.

MRI-derived body segment parameters of children differ from age-based estimates derived using photogrammetry

Body segment parameters are required when researching joint kinetics using inverse dynamics models. However, the only regression equations for estimating pediatric body segment parameters across a wide age range were developed, using photogrammetry, based on 12 boys and have not been validated to date (Jensen, R.K., 1986. Body segment mass, radius and radius of gyration proportions of children. Journal of Biomechanics 19, 359–368). To assess whether these equations could validly be applied to girls, we asked whether body segment parameters estimated by the equations differ from parameters measured using a validated magnetic resonance imaging (MRI) method. If so, do the differences cause significant differences in joint kinetics during normal gait? Body segment parameters were estimated from axial MRIs of the left thigh and shank of 10 healthy girls (9.6±0.9 years) and compared to those from Jensen's equations. Kinematics and kinetics were collected for 10 walking trials. Extrema in hip and knee moments and powers were compared between the two sets of body segment parameters. With the exception of the shank mass center and radius of gyration, body segment parameters measured using MRI were significantly different from those estimated using regression equations. These systematic differences in body segment parameters resulted in significant differences in sagittal-plane joint moments and powers during gait. Nevertheless, it is doubtful that even the greatest differences in kinetics are practically meaningful (0.3%BW×HT and 0.7%BW×HT/s for moments and power at the hip, respectively). Therefore, body segment parameters estimated using Jensen's regression equations are a suitable substitute for more detailed anatomical imaging of 8–10-year-old girls when quantifying joint kinetics during gait.

The kinematics and kinetics of turning: limb asymmetries associated with walking a circular path

The biomechanics of changing direction while walking has been largely neglected despite its obvious relevancy to functional mobility. The world is filled with turns that must be negotiated. These turns carry an increased risk of injury due to a decrease in stability. A VICON 612 system measured joint kinematics and kinetics on 10 normal subjects for straight line walking (ST); turning, inside foot strike (IN); and turning, outside foot strike (OUT). All trials were completed at a self-selected walking speed and across a range of speeds from 0.6 to 1.3 m/s; the turn radius was 1 m. Significant differences between the conditions were detected using a mixed effects repeated measures ANCOVA with walking speed as a covariate. The most pronounced differences were demonstrated in the mediolateral ground reaction force impulse: in straight walking the impulses tended to shift the body toward the contralateral limb. In turning, the IN and OUT impulses shifted the body toward the ipsilateral and contralateral limbs, respectively. Knee flexion during stance was increased on the IN limb, while ankle plantarflexion increased on the OUT limb consistent with body lean during turning; differences in joint kinetics during turning were negligible. Self-selected turning was significantly slower than walking straight ahead (0.96+/-0.12 m/s versus 1.61+/-0.22 m/s) and turning at very slow speeds showed a non-uniform center of mass trajectory. Understanding the mechanisms of turning will provide insights driving design, therapy and intervention to increase functional navigation in amputees, the elderly and individuals with neuromuscular pathologies.

Identification of kinetic differences between fallers and nonfallers in the elderly.

Falls are a major cause of decreased mobility and disability in the elderly. Multiple factors are believed to contribute to falling. Among these, gait abnormalities have drawn attention as a possible risk factor. Although previous studies have revealed few differences in gait parameters compared with similar aged controls, it was hypothesized that because of intrinsic differences in balance and motor control, we would observe differences in joint kinetics. In this study, 15 subjects (mean age, 77 +/- 9 yr), who had at least 2 mo of repeated falls from an unclear cause, were evaluated in a gait laboratory and were compared with a control group of 15 subjects (mean age, 75 +/- 5 yr) with no history of falls. Analysis of data demonstrated a significantly greater peak torque in the falls group for the following: hip flexion, hip adduction, knee extension, knee varum, ankle dorsiflexion, and ankle eversion (P < 0.003 in each comparison). Also, ankle plantarflexion torque was significantly decreased in the falls group (P = 0.001). Joint powers showed different absorption at the knee and ankle in the falls group. The discovery of these kinetic differences may provide further insight into the mechanism of falls in the elderly and, more importantly, lead to identifiable markers to detect those who may be susceptible to falls.