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1.
Many sports associated with anterior cruciate ligament (ACL) injury require athletes attend to a ball during participation. We investigated effects of attending to a ball on lower extremity mechanics during a side-cut maneuver and if these effects are consistent for males and females. Sagittal and frontal plane hip and knee kinematics and joint moments were measured during side-cut maneuvers in 19 male and 19 female National Collegiate Athletic Association division III basketball players. Participants also experienced two side-cut conditions that required attention to a ball. Our results did not indicate that the effect of attention varies with gender. However, during side-cut conditions while attending to a ball, internal knee adductor moment was 20% greater (p = 0.03) and peak knee flexion angle was 4 degrees larger (p < 0.01). Females demonstrated 5 degrees less hip flexion (p = 0.046), 12 degrees less knee flexion (p < 0.01), and 4 degrees more knee abduction (p = 0.026) at initial contact during all side-cut conditions than males. Attention to a ball may affect lower extremity mechanics relevant to ACL injury. The validity of laboratory studies of lower extremity mechanics for sports that include attention to a ball may be increased if participants are required to attend to a ball during the task.  相似文献   

2.
The incidence of patellofemoral pain (PFP) is 2 times greater in females compared with males of similar activity levels; however, the exact reason for this discrepancy remains unclear. Abnormal mechanics of the hip and knee in the sagittal, frontal, and transverse planes have been associated with an increased risk of PFP. The purpose of this study was to compare the mechanics of the lower extremity in males and females during running in order to better understand the reason(s) behind the sex discrepancy in PFP. Three-dimensional kinematic and kinetic data were collected as male and female participants completed overground running trials at a speed of 4.0 m · s?1 (±5%). Patellofemoral joint stress (PFJS) was estimated using a sagittal plane knee model. The kinematics of the hip and knee in the frontal and transverse planes were also analysed. Male participants demonstrated significantly greater sagittal plane peak PFJS in comparison with the female participants (P < .001, ES = 1.9). However, the female participants demonstrated 3.5° greater peak hip adduction and 3.4° greater peak hip internal rotation (IR). As a result, it appears that the sex discrepancy in PFP is more likely to be related to differences in the kinematics of the hip in the frontal and transverse planes than differences in sagittal plane PFJS.  相似文献   

3.
Many sports associated with anterior cruciate ligament (ACL) injury require athletes attend to a ball during participation. We investigated effects of attending to a ball on lower extremity mechanics during a side-cut maneuver and if these effects are consistent for males and females. Sagittal and frontal plane hip and knee kinematics and joint moments were measured during side-cut maneuvers in 19 male and 19 female National Collegiate Athletic Association division III basketball players. Participants also experienced two side-cut conditions that required attention to a ball. Our results did not indicate that the effect of attention varies with gender. However, during side-cut conditions while attending to a ball, internal knee adductor moment was 20% greater (p = 0.03) and peak knee flexion angle was 4° larger (p < 0.01). Females demonstrated 5° less hip flexion (p = 0.046), 12° less knee flexion (p < 0.01), and 4° more knee abduction (p = 0.026) at initial contact during all side-cut conditions than males. Attention to a ball may affect lower extremity mechanics relevant to ACL injury. The validity of laboratory studies of lower extremity mechanics for sports that include attention to a ball may be increased if participants are required to attend to a ball during the task.  相似文献   

4.
Previous studies have linked footwear traction to lower extremity non-contact injury; however, these studies mainly focussed on rotational traction exclusively. While studies have shown that increases in traction lead to increases in joint loading, represented by joint moments, these studies failed to determine how the individual components of rotational and translational traction affect joint loading. Therefore, this study investigated how each component of traction independently affects lower extremity joint loading. Traction testing was performed using a robotic testing machine on three shoes that had independent alterations of translational and rotational traction. All testing was conducted on a sample piece of artificial turf. Kinematic and kinetic data were then collected on 10 athletes performing two cutting movements in each shoe condition. As rotational and translational traction were independently altered, decreased rotational traction led to significant decreases in transverse and frontal plane joint loading at the ankle and knee joints, while increases in translational traction led to increases in frontal plane joint loading at the ankle and knee joints. Increases in joint loading in the transverse and frontal planes are one of the possible mechanisms of lower extremity non-contact injury. Both translational and rotational traction can independently alter the joint loading.  相似文献   

5.
Running on side-sloped surfaces is a common obstacle in the environment; however, how and to what extent the lower extremity kinematics adapt is not well known. The purpose of this study was to determine the effects of side-sloped surfaces on three-dimensional kinematics of hip, knee, and ankle during stance phase of running. Ten healthy adult males ran barefoot along an inclinable runway in level (0°) and side-sloped (10° up-slope and down-slope inclinations, respectively) configurations. Right hip, knee, and ankle angles along with their time of occurrence were analysed using repeated measures MANOVA. Up-slope hip was more adducted (p = 0.015) and internally rotated (p = 0.030). Knee had greater external rotations during side-sloped running at heel-strike (p = 0.005), while at toe-off, it rotated externally and internally during up-slope and down-slope running, respectively (p = 0.001). Down-slope ankle had greatest plantar flexion (p = 0.001). Up-slope ankle had greatest eversion compared with down-slope (p = 0.043), while it was more externally rotated (p = 0.030). These motion patterns are necessary to adjust the lower extremity length during side-sloped running. Timing differences in the kinematic events of hip adduction and external rotation, and ankle eversion were observed (p = 0.006). Knowledge on these alterations is a valuable tool in adopting strategies to enhance performance while preventing injury.  相似文献   

6.
The arm swing in hockey skating can have a positive effect on the forces produced by each skate, and the resulting velocity from each push off. The main purpose of this study was to measure the differences in ground reaction forces (GRFs) produced from an anteroposterior versus a mediolateral style hockey skating arm swing. Twenty-four elite-level female hockey players performed each technique while standing on a ground-mounted force platform, and all trials were filmed using two video cameras. Force data was assessed for peak scaled GRFs in the frontal and sagittal planes, and resultant GRF magnitude and direction. Upper limb kinematics were assessed from the video using Dartfish video analysis software, confirming that the subjects successfully performed two distinct arm swing techniques. The mediolateral arm swing used a mean of 18.38° of glenohumeral flexion/extension and 183.68° of glenohumeral abduction/adduction while the anteroposterior technique used 214.17° and 28.97° respectively. The results of this study confirmed that the mediolateral arm swing produced 37% greater frontal plane and 33% less sagittal plane GRFs than the anteroposterior arm swing. The magnitudes of the resultant GRFs were not significantly different between the two techniques; however, the mediolateral technique produced a resultant GRF with a significantly larger angle from the direction of travel (44.44°) as compared to the anteroposterior technique (31.60°). The results of this study suggest that the direction of GRFs produced by the mediolateral arm swing more closely mimic the direction of lower limb propulsion during the skating stride.  相似文献   

7.
Abstract

In this study, we examined hamstring muscle activation at different running speeds to help better understand the functional characteristics of each hamstring muscle. Eight healthy male track and field athletes (20.1 ± 1.1 years) performed treadmill running at 50%, 75%, 85%, and 95% of their maximum velocity. Lower extremity kinematics of the hip and knee joint were calculated. The surface electromyographic activities of the biceps femoris and semitendinosus muscles were also recorded. Increasing the running speed from 85% to 95% significantly increased the activation of the hamstring muscles during the late swing phase, while lower extremity kinematics did not change significantly. During the middle swing phase, the activity of the semitendinosus muscle was significantly greater than that of the biceps femoris muscle at 75%, 85%, and 95% of running speed. Statistically significant differences in peak activation time were observed between the biceps femoris and semitendinosus during 95%max running (P < 0.05 for stance phase, P < 0.01 for late swing phase). Significant differences in the activation patterns between the biceps femoris and semitendinosus muscles were observed as running speed was increased, indicating that complex neuromuscular coordination patterns occurred during the running cycle at near maximum sprinting speeds.  相似文献   

8.
The purpose of this study was to evaluate the effects of a functional agility fatigue protocol on lower extremity biomechanics between two unanticipated tasks (stop-jump and sidestep). The subjects consisted of fifteen female collegiate soccer athletes (19±0.7 years, 1.67±0.1 m, 61.7±8 kg) free of lower extremity injury. Participants performed five trials of stop-jump and sidestep tasks. A functional short-term agility protocol was performed, and immediately following participants repeated the unanticipated running tasks. Lower extremity kinematic and kinetic values were obtained pre and post fatigue. Repeated measures analyses of variance were conducted for each dependent variable with an alpha level set at 0.05. Knee position post-fatigue had increased knee internal rotation (11.4±7.5° vs. 7.9±6.5° p=0.011) than pre-fatigue, and a decreased knee flexion angle (-36.6±6.2° vs. ?40.0±6.3°, p = 0.003), as well as hip position post-fatigue had decreased hip flexion angle (35.5±8.7° vs. 43.2±9.5°, p = 0.002). A quick functional fatigue protocol altered lower extremity mechanics of Division I collegiate soccer athletes during landing tasks. Proper mechanics should be emphasized from the beginning of practice/game to aid in potentially minimizing the effects of fatigue in lower extremity mechanics.  相似文献   

9.
Curve running requires the generation of centripetal force altering the movement pattern in comparison to the straight path run. The question arises which kinematic modulations emerge while bend sprinting at high velocities. It has been suggested that during curve sprints the legs fulfil different functions. A three-dimensional motion analysis (16 high-speed cameras) was conducted to compare the segmental kinematics of the lower extremity during the stance phases of linear and curve sprints (radius: 36.5 m) of six sprinters of national competitive level. Peak joint angles substantially differed in the frontal and transversal plane whereas sagittal plane kinematics remained unchanged. During the prolonged left stance phase (left: 107.5 ms, right: 95.7 ms, straight: 104.4 ms) the maximum values of ankle eversion (left: 12.7°, right: 2.6°, straight: 6.6°), hip adduction (left: 13.8°, right: 5.5°, straight: 8.8°) and hip external rotation (left: 21.6°, right: 12.9°, straight: 16.7°) were significantly higher. The inside leg seemed to stabilise the movement in the frontal plane (eversion–adduction strategy) whereas the outside leg provided and controlled the motion in the horizontal plane (rotation strategy). These results extend the principal understanding of the effects of curve sprinting on lower extremity kinematics. This helps to increase the understanding of nonlinear human bipedal locomotion, which in turn might lead to improvements in athletic performance and injury prevention.  相似文献   

10.
The potential to use the vertical jump (VJ) to assess both athletic performance and risk of anterior cruciate ligament (ACL) injury could have widespread clinical implications since VJ is broadly used in high school, university, and professional sport settings. Although drop jump (DJ) and VJ observationally exhibit similar lower extremity mechanics, the extent to which VJ can also be used as screening tool for ACL injury risk has not been assessed. This study evaluated whether individuals exhibit similar knee joint frontal plane kinematic and kinetic patterns when performing VJs compared with DJs. Twenty-eight female collegiate athletes performed DJs and VJs. Paired t-tests indicated that peak knee valgus angles did not differ significantly between tasks (p = 0.419); however, peak knee internal adductor moments were significantly larger during the DJ vs. VJ (p < 0.001). Pearson correlations between the DJ and VJ revealed strong correlations for knee valgus angles (r = 0.93, p < 0.001) and for internal knee adductor moments (r = 0.82, p < 0.001). Our results provide grounds for investigating whether frontal plane knee mechanics during VJ can predict ACL injuries and thus can be used as an effective tool for the assessment of risk of ACL injury in female athletes.  相似文献   

11.
Abstract

The knee is a common site of injury in netball players. In this study, 10 high-performance netball players underwent a biomechanical assessment of their single leg landing technique whilst receiving a pass. Three-dimensional video and ground reaction force data were recorded using a motion analysis system. Net internal knee joint moments were calculated using a rigid body analysis and inverse dynamics. The kinematics of the support leg and front-on video footage was used to investigate whether players adhered to guidelines on safe and effective landing strategies. Results indicated that for most players the internal valgus moment was the largest frontal plane knee moment during the landing phase. This may reflect a relatively greater need to resist varus knee excursion or may be related to the kinematics of the hip. For 6 of the 10 players the rapid change to an internal knee valgus moment coincided with hip adduction. Since an increase in the magnitude of the internal valgus moment may increase the compressive forces in the medial compartment of the knee, further work should be undertaken to determine if a neuromuscular training intervention to improve the strength of the hip musculature may be beneficial for these players. A large relative excursion of the knee compared to the hip may indicate that these players had a greater reliance on the more distal segments of the lower extremity for the attenuation of the ground reaction forces. This information may be used to better understand potential knee injury mechanisms in netball players.  相似文献   

12.
Running on a treadmill is an activity that is novel to many people. Thus, a familiarisation period may be required before reliable and valid determinations of biomechanical parameters can be made. The current study investigated the time required for treadmill familiarisation under barefoot and shod running conditions. Twenty-six healthy men, who were inexperienced in treadmill running, were randomly allocated to run barefoot or shod for 20 minutes on a treadmill at a self-selected comfortable pace. Sagittal-plane kinematics for the ankle, knee and hip, and ground reaction force and spatio-temporal data were collected at two-minute intervals. For the barefoot condition, temporal differences were observed in peak hip flexion and peak knee flexion during swing. For the shod condition, temporal differences were observed for peak vertical ground reaction force. No temporal differences were observed after 8 minutes for either condition. Reliability analysis revealed high levels of consistency (ICC > 0.90) across all consecutive time-points for all dependent variables for both conditions after 8 minutes with the exception of maximal initial vertical ground reaction force loading rate. Participants in both barefoot and shod groups were therefore considered familiarised to treadmill running after 8 minutes.  相似文献   

13.
Chronic ankle instability (CAI) is a condition resulting from a lateral ankle sprain. Shank-rearfoot joint-coupling variability differences have been found in CAI patients; however, joint-coupling variability (VCV) of the ankle and proximal joints has not been explored. Our purpose was to analyse VCV in adults with and without CAI during gait. Four joint-coupling pairs were analysed: knee sagittal-ankle sagittal, knee sagittal-ankle frontal, hip frontal-ankle sagittal and hip frontal-ankle frontal. Twenty-seven adults participated (CAI:n = 13, Control:n = 14). Lower extremity kinematics were collected during walking (4.83 km/h) and jogging (9.66 km/h). Vector-coding was used to assess the stride-to-stride variability of four coupling pairs. During walking, CAI patients exhibited higher VCV than healthy controls for knee sagittal-ankle frontal in latter parts of stance thru mid-swing. When jogging, CAI patients demonstrated lower VCV with specific differences occurring across various intervals of gait. The increased knee sagittal-ankle frontal VCV in CAI patients during walking may indicate an adaptation to deal with the previously identified decrease in variability in transverse plane shank and frontal plane rearfoot coupling during walking; while the decreased ankle-knee and ankle-hip VCV identified in CAI patients during jogging may represent a more rigid, less adaptable sensorimotor system ambulating at a faster speed.  相似文献   

14.
目的:确定跑步疲劳进程中下肢生物力学模式的变化,包括垂直和前后地面反作用力(ground reaction force,GRF)、垂直地面反作用力(vertical ground reaction force,vGRF)负载率、关节力学和刚度。方法:14名男性受试,采用Vicon红外摄像头和Bertec三维测力跑台,每隔2 min采集受试疲劳干预中的15 s GRF数据以及标记点轨迹。受试需穿着统一的跑鞋在测力跑台以恒速3.33 m/s跑至疲劳。满足以下标准时,干预结束:1)最大心率大于当下年龄的90%;2)受试不能继续跑步。对比受试跑至疲劳进程中4个时刻(疲劳前、33%、67%和100%)的着地冲击和下肢三关节触地角度、最大角度、关节活动度、角度变化量、关节蹬伸力矩和刚度等特征,采集并分析受试安静状态、疲劳后即刻、疲劳后4 min、疲劳后9 min的血乳酸浓度。结果:与疲劳前相比,1)血乳酸浓度在疲劳后即刻、疲劳后4 min和疲劳后9 min均显著增加;2)垂直/前后矢状轴GRF和vGRF负载率等参数在疲劳干预过程中均未观察到显著性变化;3)髋关节活动度在疲劳过程的33%、67%和100%时刻显著增加,膝关节活动度在67%时刻显著增加;4)踝关节运动学及踝、膝和髋关节的蹬伸力矩峰值均无变化;5)垂直刚度在67%和100%时刻显著降低。结论:疲劳干预过程中,GRF特征参数均没有明显变化,但是观察到下肢运动学和动力学模式的非线性改变。特别是从疲劳干预中期开始,人体下肢通过增加髋、膝关节活动度并减小垂直刚度实现“软着陆”策略,维持相似的冲击力特征,以减小长时间跑步可能带来损伤的风险。  相似文献   

15.
Knee injuries in golf comprise approximately 8% of all injuries, and are considered to result from overuse, technical faults or a combination of those factors. This review examines factors involved in injury, including the structure of the knee joint, kinematics and kinetics of the golf swing, forces sustained by knee joint structures and the potential for joint injury as well as injury prevention strategies. The golf swing generates forces and torques which tend to cause internal or external rotation of the tibia on the femur, and these are resisted by the knee ligaments and menisci. Research has shown that both maximum muscle forces and the forces sustained during a golf swing are less than that required to cause damage to the ligaments. However, the complex motion of the golf swing, involving both substantial forces and ranges of rotational movement, demands good technique if the player is to avoid injuring their knee joint. Most knee injury in golf is likely related to joint laxity, previous injuries or arthritis, and such damage may be exacerbated by problems in technique or overuse. In addition to appropriate coaching, strategies to remedy discomfort include specific exercise programmes, external bracing, orthotics and equipment choices.  相似文献   

16.
Abstract

This study investigated the effects of knee localised muscle damage on running kinematics at varying speeds. Nineteen young women (23.2 ± 2.8 years; 164 ± 8 cm; 53.6 ± 5.4 kg), performed a maximal eccentric muscle damage protocol (5 × 15) of the knee extensors and flexors of both legs at 60 rad · s-1. Lower body kinematics was assessed during level running on a treadmill at three speeds pre- and 48 h after. Evaluated muscle damage indices included isometric torque, muscle soreness and serum creatine kinase activity. The results revealed that all indices changed significantly after exercise, indicating muscle injury. Step length decreased and stride frequency significantly increased 48 h post-exercise only at the fastest running speed (3 m · s-1). Support time and knee flexion at toe-off increased only at the preferred transition speed and 2.5 m · s-1. Knee flexion at foot contact, pelvic tilt and obliquity significantly increased, whereas hip extension during stance-phase, knee flexion during swing-phase, as well as knee and ankle joints range of motion significantly decreased 48 h post-exercise at all speeds. In conclusion, the effects of eccentric exercise of both knee extensors and flexors on particular tempo-spatial parameters and knee kinematics of running are speed-dependent. However, several pelvic and lower joint kinematics present similar behaviour at the three running speeds examined. These findings provide new insights into how running kinematics at different speeds are adapted to compensate for the impaired function of the knee musculature following muscle damage.  相似文献   

17.
To determine the contributions of the motions of the body segments to the vertical ground reaction force (Fz), the joint torques produced by the leg muscles, and the time course of vertical velocity generation during a vertical jump, 15 men were videotaped performing countermovement vertical jumps from a force plate with and without an arm swing. Linear kinematic, Fz, and joint torque data were computed and compared using repeated measures analysis of variance. Maximum jump height was significantly larger in the arm swing jumps compared to the no arm swing jumps and was due to both a higher height of the center of mass (CM) at takeoff (54%) and a larger vertical velocity of the CM at takeoff (46%). The net vertical impulse created during the propulsive phase of the arm swing jumps was greater due to a trend of an increased duration (0.021 s) of the propulsive phase and not to larger average values of Fz. In the arm swing jumps, the arm motion resulted in the arms making a larger maximal contribution to Fz during the middle of the propulsive phase and decreased the negative contribution of the trunk-head and thigh to Fz late in the propulsive phase. Last, the arm swing decreased the extensor torques at the hip (13%), knee (10%), and ankle (10%) early in the propulsive phase but augmented these same extensor torques later in the propulsive phase.  相似文献   

18.
A proficient serve is critical to successful tennis performance, and consequently coaches and players devote considerable time refining this stroke. In so doing, a wide variety of interventions are used or trialled, generally with very little empirical support. This study examined the efficacy of a commonly used service intervention, where players focus on exaggerating their finish (arabesque) position to promote specific changes in lower limb and trunk kinematics. The kinematics of eight high-performance junior players hitting flat serves were compared to the acute changes in kinematics elicited by the arabesque follow through position on serves using a 10-camera VICON MX motion analysis system. The significantly greater front (landing leg) hip flexion (p < 0.05) and forward trunk flexion (p < 0.05) confirmed the more exaggerated arabesque landing position following the arabesque instruction. The arabesque instruction resulted in increased frontal plane trunk range of motion and peak angular velocity in the forward swing, and increased leg drive during the drive phase. Practically, the results support the use of the arabesque instruction, effectively promoting the desired acute changes in trunk kinematics (i.e. increased frontal plane trunk rotation angular velocity) and leg drive (i.e. increased back knee extension angular velocity and front/back vertical hip velocity).  相似文献   

19.
Limb dominance theory suggests that females tend to be more one-leg dominant and exhibit greater kinematic and kinetic leg asymmetries than their male counterparts, contributing to the increased risk of anterior cruciate ligament injury among female athletes. Thus, the purpose of this study was to examine the influences of sex and limb dominance on lower extremity joint mechanics during unilateral land-and-cut manoeuvres. Twenty-one women and 21 men completed land-and-cut manoeuvres on their dominant limb as well as their nondominant limb. Three-dimensional kinematics and kinetics were calculated bilaterally for the entire stance phase of the manoeuvre. Women performed land-and-cut manoeuvres with altered hip motions and loads as well as greater knee abduction at touchdown compared to men. Dominant limb land-and-cut manoeuvres where characterised by decreased hip flexion at touchdown as well as decreased hip flexion and adduction range of motion compared to nondominant land-and-cuts regardless of sex. The observed sex differences are consistent with previous research regarding mechanisms underlying the sex disparity in anterior cruciate ligament injury rates. However, observed differences regarding limb dominances appear somewhat arbitrary and did not suggest that the dominant or nondominant limb would be at increased risk of anterior cruciate ligament injury.  相似文献   

20.
Although landing in a plantarflexion and inversion position is a well-known characteristic of lateral ankle sprains, the associated kinematics of the knee and hip is largely unknown. Therefore, the purpose of this study was to examine the changes in knee and hip kinematics during landings on an altered landing surface of combined plantarflexion and inversion. Participants performed five drop landings from 30 cm onto a trapdoor platform in three different conditions: flat landing surface, 25° inversion, or a combined 25° plantarflexion and 25° inversion. Kinematic data were collected using a seven camera motion capture system. A 2 × 3 (leg × surface) repeated measures ANOVA was used for statistical analysis. The combined surface showed decreased knee and hip flexion range of motion (ROM) and increased knee abduction ROM (p < 0.05). The altered landing surface creates a stiff landing pattern where reductions in sagittal plane motion are transferred to the frontal plane, resulting in increased knee abduction. A stiff landing pattern is frequently related to increased risk of anterior cruciate ligament injury. It may be beneficial for athletes at risk to train for alternate methods of increasing their sagittal plane motion of the knee and hip with active knee or trunk flexion.  相似文献   

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