Correlation between the Angle of Lateral Tibial Rotation and the Ratio of Medial and Lateral Hamstring Muscle Activities during Standing Knee Flexion

Effects of the abdominal drawing-in maneuver on hamstring rotational activity and pelvic stability in females

BACKGROUND

The medial hamstring (MH) and lateral hamstring (LH) can be selectively trained through tibial internal and external rotation during prone knee flexion. However, no study has identified how a combined tibial rotation and lumbo-pelvic stability strategy influences MH and LH muscle activities.

OBJECTIVE

To investigate the combined effects of tibial rotation and the abdominal drawing-in maneuver (ADIM) on MH and LH muscle activities as well as pelvic rotation during prone knee flexion.

METHODS

Fifteen female volunteers performed prone knee flexion with tibial internal and external rotation, with and without the ADIM. Under each condition, MH and LH muscle activities were measured by surface electromyography (EMG), and the pelvic rotation angle by a smartphone inclinometer application.

RESULTS

The results showed increased MH (without the ADIM: p< 0.001, effect size (d) = 2.05; with the ADIM: p< 0.001, d= 1.71) and LH (without the ADIM: p< 0.001, d= 1.64; with the ADIM: p= 0.001, d= 1.58) muscle activities under internal and external tibial rotation, respectively. However, addition of the ADIM led to increased MH (internal tibial rotation: p= 0.001, d= 0.67; external tibial rotation: p= 0.019, d= 0.45) and LH (internal tibial rotation: p= 0.003, d= 0.79; external tibial rotation: p< 0.001, d= 1.05) muscle activities combined with reduced pelvic rotation (internal tibial rotation: p< 0.001, d= 3.45; external tibial rotation: p< 0.001, d= 3.01) during prone knee flexion.

CONCLUSIONS

These findings suggest that the ADIM could be useful for reducing compensatory pelvic rotation and enhancing selective muscle activation in the MH and LH, according to the direction of tibial rotation, during prone knee flexion.

The ratio of medial and lateral hamstring muscle thickness does not correlate with the lateral tibial rotation angle in the standing position in healthy young adults

[Purpose] To investigate the relationship between the lateral tibial rotation angle during knee joint flexion and the medial and lateral hamstring muscle thickness ratio during knee joint extension while resting, doing nothing, in upright standing position. The lateral tibial torsion is an important factor of orthopedic knee joint diseases as well as other weight bearing joint diseases such as osteoarthritis, meniscus syndrome, anterior cruciate ligament rupture, etc. [Subjects and Methods] Thirty healthy young adults participated in this study. The thickness of the medial and lateral hamstrings was measured using ultrasonographic imaging technique during knee extension in a resting position. The angle of tibial rotation was measured with 2D motion analysis during knee flexion in a half kneeling position. Pearson's correlation coefficient was used to test the relationship. [Results] There is no significant relationship between the angle of lateral tibial rotation and the ratio of hamstring muscle thickness. [Conclusion] These results demonstrate that lateral tibial rotation is not affected by hamstrings during rest in a standing position.

Comparison of knee laxity and isokinetic muscle strength in patients with a posterior cruciate ligament injury

[Purpose] The aim of this study was to compare knee laxity and isokinetic muscle strength in patients with an isolated posterior cruciate ligament injury. [Subjects and Methods] Twenty high school rugby players with a previous posterior cruciate ligament injury and abnormal findings higher than surgical grade I were included. Laxity with 132 N of pressure was measured using Kneelax 3 to assess the stability of the posterior cruciate ligament, and flexor and extensor torques were measured at 60°/sec, 180°/sec, and 240°/sec to measure the isokinetic muscle strength of the knee joint. The average and standard deviation values were extracted from all data to assess the measured data. [Results] Regarding the ipsilateral and contralateral laxity, the deviation value at the peak force and maximum manual drawer was statistically significant. The peak torque and peak torque per body weight in isokinetic measurements were significantly different only for knee extensor torque at 60°/sec, 180°/sec, and 240°/sec. [Conclusion] Return to normal activities post injury is important. Thus base data gathered by comparing patients' ipsilateral and contralateral sides will serve as essential criteria for structuring future rehabilitation programs to facilitate functional improvements.