Construction of an isokinetic horizontal eccentric towing device to improve sprinting performance

Horizontal eccentric towing (HET) is a novel modality that delivers an eccentric overload to the musculature as an athlete attempts to move forward in a sprint stance whilst being pulled backwards. A device, called the HET, has been developed to automate this movement. Similar to a winch retracting an anchor on a boat, the HET device pulls an athlete that is tethered inwards and the athlete must resist this motion in a maximal manner, whilst maintaining a sprint stance. The HET device provides an isokinetic training modality by towing athletes inwards at a constant velocity. The HET device is operated by an electric 10 kW AC synchronous servo gearmotor. The motor is controlled by a variable speed drive (VSD) and programmable logic controller (PLC), which allow for accurate speed, position and torque control. A touchscreen PC runs the user interface displaying real-time force and speed measures. The HET device can produce a maximum towing force of 2.8 kN at ground velocities of up to 3.58 m/s. There is a separate safety PLC that triggers a safety-rated brake system when the E-stop buttons are pushed. This is paramount for athlete safety. In this technical note, the components used in the construction of the HET device will be detailed and insights into a novel stimulus will be offered, as well as a guide to develop and automate similar eccentric movements.

Comparative Effects of Isokinetic Training and Virtual Reality Training on Sports Performances in University Football Players with Chronic Low Back Pain-Randomized Controlled Study

Objective. The objective of this study is to find and compare the effects of isokinetic training and virtual reality training on sports performances in university football players with chronic low back pain. Design. This is a randomized, double-blinded controlled study. Methods. The study was conducted on 45LBP participants at university hospital. First group (n = 15) received isokinetic training, second group (n = 15) received virtual reality training, and the control group (n = 15) received conventional training exercises for four weeks. Clinical (pain intensity and player wellness) and sports performance (40 m sprint, 4 × 5 m sprint, submaximal shuttle running, countermovement jump, and squat jump) scores were measured at baseline, after 4 weeks, 8 weeks, and 6 months. Results. Four weeks following training VRT group shows more significant changes in pain intensity and player wellness scores than IKT and control groups (p≤0.001). Sports performance variables (such as 40 m sprint, 4 × 5 m sprint, submaximal shuttle running, countermovement jump, and squat jump) scores also show significant improvement in VRT group than the other two groups (p≤0.001). Conclusion. Overall, our study suggests that strength training through virtual reality training protocol improves pain and sports performances than isokinetic training and other conventional trainings in university football players with chronic low back pain.

CORRELATION BETWEEN ECCENTRIC TRAINING AND FUNCTIONAL TESTS IN SUBJECTS WITH RECONSTRUCTED ACL

ABSTRACT Introduction: Eccentric training and jump tests are widely used to recover and measure deficits in knee strength and functionality after anterior cruciate ligament (ACL) reconstruction. Objective: To correlate knee extension and flexion torque generated by eccentric isokinetic training, with functional jump tests in subjects with reconstructed ACL. Method: Sixteen men with unilateral ACL reconstruction were assessed before and after 12 weeks of eccentric isokinetic training of knee flexors and extensors (3×10 MVC, 2x/week) at 30°/s for extension and flexion torque (isometric; concentric and eccentric at 30 and 120°/s) and functional jump tests (single, triple, cross and figure of 8). Inter- and intra-limb pre- and post-training mean peak torque (MPT), distance and jump test times were compared along with the correlations between these variables, considering P<0.05. Results: The affected limb (AL) showed significant gain of extension and flexion torque (P<0.01) in the different test categories and velocities evaluated. In the non-affected limb (NAL), this only occurred in the eccentric category (30 and 120°/s), in the extension (P<0.01) and flexion (P<0.05 and P<0.01) torques, respectively. In the jumps, there was an increase in distance (single and triple; P<0.05) and a decrease in time (crossed and figure of 8; P<0.01), however, MPT x Jump correlations were weak (r<0.3) in the pre and post-training period in both limbs. Conclusion: Despite the gain in knee extension and flexion torque and jumping performance, the expected correlation was not satisfactory, suggesting that knee functionality involves other variables inherent to motor control. Level of Evidence IV; Type of study: Case series.