Wyniki wyszukiwania - BazTech

1

Lower extremity muscle strength, postural stability and functional movement screen in female basketball players after ACL reconstruction : Preliminary report

Wrzesień Zuzanna, Truszczynska-Baszak Aleksandra, Rzepka Remigiusz

Acta of Bioengineering and Biomechanics

|

2019

|

Vol. 21, no. 2

71--81

EN

The anterior cruciate ligament (ACL) tear is a common injury in basketball. Its consequence is a long absence from training, resulting from surgical treatment and long physiotherapy. The aim of the study was to assess muscle strength, postural stability and functional movements in female basketball players, who returned to professional sport careers after anterior cruciate ligament reconstruction. Methods: The study population consisted of 10 female basketball players after surgical reconstruction of anterior cruciate ligament. The control group consisted of 10 players without ACL injury. We used the Biodex System 4 Pro dynamometer to assess the muscle strength of the knee. We used it to conduct the test of flexors and extensors of the knee in isokinetic conditions. We also used Keiser Power Squat A300 in the single leg squat to measure power and the Biodex Balance SD dynamographic platform to assess balance in single leg stance. Results: We found deficits in both movement patterns and in muscle strength in the study population, compared to control group. Conclusions: The basketball players after ACL reconstruction had significant differences between the operated and non-operated limb. The differences may predispose them towards repeated ACL injuries.

2

Application of force-length curve for determination of leg stiffness during a vertical jump

Struzik A., Zawadzki J.

Acta of Bioengineering and Biomechanics

|

2016

|

Vol. 18, no. 2

163--171

EN

Purpose: The aim of this study was to present the methodology for estimation of a leg stiffness during a countermovement jump. The question was asked whether leg stiffness in the countermovement and take-off phases are similar to each other as demonstrated in previous reports. It was also examined whether the stiffness in left lower limb is similar to the one in right lower limb. Methods: The research was conducted on 35 basketball players. Each participant performed three countermovement jumps with arm swing to the maximum height. Measurements employed a Kistlerforce plate and a BTS SMART system for motion analysis. Leg stiffness (understood as an inclination of the curve of ground reaction forces vs. length) was computed for these parts of countermovement and take-off phases where its value was relatively constant and F(∆l) relationship was similar to linear. Results: Mean value (±SD) of total stiffness of both lower limbs in the countermovement phase was 7.1 ± 2.3 kN/m, whereas this value in the take-off phase was 7.5 ± 1 kN/m. No statistically significant differences were found between the leg stiffness in the countermovement and the take-off phases. No statistically significant differences were found during the comparison of the stiffness in the right and left lower limb. Conclusions: The calculation methodology allows us to estimate the value of leg stiffness based on the actual shape of F(∆l) curve rather than on extreme values of ∆F and ∆l. Despite different tasks of the countermovement and the take-off phases, leg stiffness in these phases is very similar. Leg stiffness during a single vertical jump maintains a relatively constant value in the parts with a small value of acceleration.

3

Leg stiffness during phases of countermovement and take-off in vertical jump

Struzik A., Zawadzki J.

Acta of Bioengineering and Biomechanics

|

2013

|

Vol. 15, no. 2

113--118

EN

With respect to cyclic movements such as human gait, running or hopping, leg stiffness is a little variable parameter. The aim of this study was to investigate changes in leg stiffness during the phase of countermovement and take-off when performing a single maximum counter-movement jump. Kistler force plates and a BTS SMART system for comprehensive motion analysis were employed in the study. The study covered a group of 12 athletes from university basketball teams. Leg stiffness was calculated in those parts of countermovement and take-off phases where its level is relatively constant and the relationship F(Δl) is similar to linear one. Mean total stiffness (±SD) in both legs in the countermovement phase amounted to 6.5 ± 1.5 kN/m, whereas during the take-off phase this value was 6.9 ± 1 kN/m. No statistically significant differences were found between leg stiffness during the countermovement phase and takeoff phase in the study group at the level of significance set at α = 0.05. This suggests that the leg stiffness in phase of countermovement and phase of take-off are much similar to each other, despite different function of both phases. Similar to cyclic movements, leg stiffness turned out relatively constant when performing a single vertical jump. There are also reported statistically significant correlations between body mass, body height, length of lower limbs and leg stiffness. The stiffness analysed by the authors should be understood as quasi-stiffness because the measurements of ΔF(Δl) were made during transient states where inertia and dumping forces are likely to affect the final result.