Static loading of the knee joint results in modified single leg landing biomechanics

Anticipatory effects on side-step cutting biomechanics in Women's Australian Football League players

Objectives

Reactive side-step cutting manoeuvres are linked to anterior cruciate ligament (ACL) injuries in Women's Australian Football League (AFLW) matches. We explored knee joint moments and ground reaction forces (GRFs) in AFLW players when performing anticipated and unanticipated side-stepping.

Methods

Sixteen AFLW players (age=25.3±4.2 years; height=1.71±0.06 m; mass=68.4±4.7 kg) completed anticipated and unanticipated side-stepping trials during which full-body three-dimensional kinematics and kinetics were recorded. One-dimensional statistical parametric mapping paired t-tests were used to compare three-dimensional knee moments during weight acceptance and GRFs during the stance phase between anticipated and unanticipated conditions.

Results

Unanticipated side-stepping incurred lower knee flexion (18%-39% of stance, p<0.01) and abduction (11%-24% of stance, p<0.01) moments. Braking and propulsive GRFs were lower and higher, respectively, across the majority of stance phase (6%-90% of stance, p<0.01) in unanticipated side-stepping. Vertical GRFs were lower in unanticipated side-stepping in the early stance phase (14%-29% of stance, p<0.01).

Conclusion

Contrary to existing literature, AFLW players exhibited knee joint moments associated with reduced ACL loading when performing unanticipated side-stepping. Players appeared to adopt a 'cautious' approach to the unanticipated side-step (ie, decelerating at the change of direction), by reducing braking and vertical GRFs in the early stance phase of cutting. This approach may be implausible to employ or detrimental to performance during matches. AFLW ACL injury prevention programmes may be enhanced with greater exposure to scenarios that replicate reactive match-play demands when aiming to improve side-stepping biomechanics.

Perceptual-Cognitive Tasks Affect Landing Performance of Soccer Players at Different Levels of Fatigue

Background

There is a possible interaction between the underlying mechanisms of perceptual-cognitive tasks and motor control. For example, landing biomechanics changed during perceptual-cognitive tasks undertaken at different levels of fatigue of the athlete. Thus, this study explored the effect of perception-cognitive tasks interventions on male soccer players' landing mechanisms at different levels of fatigue.

Methods

Perceptual-cognitive tasks during games were simulated using classic multiple object tracking (MOT) paradigms, and 15 male soccer players completed MOT tasks under nonfatigue (NF), moderate fatigue (MF), and severe fatigue (SF). Landing-associated indicators were collected and calculated using a Vicon and force measuring platform.

Results

Level of fatigue and MOT task significantly affected hip and knee flexion angles, hip and knee extension moments, and vertical ground reaction force. Specifically, hip and knee flexion angles were significantly higher in MOT than non-MOT tasks at all levels of fatigue. In NF state, hip and knee extension moments were significantly smaller during MOT than non-MOT tasks. In SF state, the hip extension moment was larger during MOT than non-MOT tasks. In both MF and SF states, vertical ground reaction force was significantly higher in MOT than non-MOT tasks.

Conclusion

Although soccer players landed cautiously when not fatigued, they were significantly less able to do this and handle challenging perceptual-cognitive task movements when fatigued. Thus, landing performance is affected by perceptual-cognitive task interference in fatigue conditions.

Effect of psychological intervention care on the negative mood and hope level of elderly patients undergoing knee arthroplasty

OBJECTIVE

We explored the influence of psychological intervention care on the negative mood and hope level of elderly patients undergoing knee arthroplasty.

METHODS

A total of 98 elderly patients undergoing knee arthroplasty in our hospital were randomly divided into a control group and an observation group, each with 49 people. The control group was given routine nursing care, and the observation group was given psychological intervention care plus routine nursing care. In the study, we compared the negative mood (Emotional distress Index Scale), preoperative hope level, quality of life, Range of Motion (ROM) of the knee, score of Hospital for Special Surgery (HSS), and satisfaction in the two groups of patients.

RESULTS

Patients in the observation group had lower Xinqing index scores than the control group (P<0.001). The scores of preoperative hope level in the observation group were higher than those of the control group (P<0.001). The scores of physical function, general health, social function, emotional role, and mental health were higher in the observation group than in the control group (all P<0.01). The ROM scores of patients in the observation group were higher than those of the control group (P<0.001). The HSS scores of patients in the observation group were higher than those of the control group (P<0.001). The patients in the observation group were significantly more satisfied with the care during hospitalization than the control group.

CONCLUSION

Psychological intervention care was effective for elderly patients undergoing knee arthroplasty. It could improve patients' negative mood, hope level, quality of life, and rehabilitation effects, and is worthy of clinical promotion and application.