Deceleration profiles between the penultimate and final steps of side-step cutting are modified by planning time
Colin MS Mulligan, Samuel T Johnson, Christine D Pollard, Kim S Hannigan, Dimitrios Athanasiadis, Marc F Norcross- Physical Therapy, Sports Therapy and Rehabilitation
- Orthopedics and Sports Medicine
- General Medicine
Context
Non-contact anterior cruciate ligament (ACL) injury often occurs during rapid deceleration and change of direction maneuvers. These activities require an athlete to generate braking forces to slow down their center of mass and change direction in a dynamic environment. During pre-planned cutting, athletes can use the penultimate step for braking prior to changing direction, resulting in lesser braking demand during the final step. During reactive cutting, athletes utilize different preparatory movement strategies during the penultimate step when planning time is limited. However, differences between the deceleration profile during the penultimate and final steps of pre-planned and reactive side-step cuts remain unknown.
Objective
Comprehensively evaluate deceleration during the penultimate and final steps of pre-planned and reactive cutting.
Design
Cross-sectional.
Setting
Laboratory.
Patients or Other Participants
Thirty-six females (Age: 20.9±1.7 years; Height: 1.66±0.07 meters; Mass: 62.4±8.7 kilograms).
Main Outcome Measure(s)
Approach velocity, velocity at initial contact and cutting angle were compared between conditions. Stance time, deceleration time and biomechanical indicators of deceleration were assessed during the penultimate and final steps of pre-planned and reactive 90-degree cuts. Separate repeated-measures ANOVA models were used to assess the influence of step, condition, and their interaction on the biomechanical indicators of deceleration.
Results
Approach velocity (p=.69) and velocity at initial contact of the penultimate step (p=.33) did not differ between conditions. During reactive cutting, participants achieved a significantly lesser cutting angle (p<.001). We identified a significant step*condition for all biomechanical indicators of deceleration (p<.05).
Conclusions
A lack of planning time results in lesser penultimate step braking and greater final step braking during reactive cutting. As a result, participants exhibited a decreased cutting angle and significantly longer stance times during the final step of reactive cutting. Improving an athlete's ability to respond to an external stimulus may facilitate a more effective penultimate step braking strategy that decreases the braking demand during the final step of reactive cutting.