Assessing thigh muscle balance of male athletes with special emphasis on eccentric hamstring strength

Nordic Hamstring Exercise training induces improved lower‐limb swing phase mechanics and sustained strength preservation in sprinters

“…The established relationships rely on inverse dynamic analysis and camera‐based isokinetic tests 17,18 providing accurate and more detailed information about lower‐limb joint mechanics. The significant associations of increased peak power Hecc ( R 2 range: 53%‐65%) and DCRe moments ( R 2 range: 39%‐65%) to improvements of knee and hip joint peak moments in sprinting support their informative value in isokinetic assessments 17,18,21 . The strong association between improvements of DCRe angles and enhanced swing phase kinematics ( R 2 = 68% to hip angle@peak power knee ) was an unexpected finding.…”

“…After a static gravity correction measurement, an isokinetic warm‐up consisting of each six submaximal (~50%‐80%), discrete concentric (con) and eccentric (ecc) repetitions of the respective muscle group was conducted. The testing order was stratified such that limbs and muscle groups (H = hamstrings, Q = quadriceps) were alternatingly tested and slow velocities were executed prior to fast ones 20,21 . For knee flexion (110‐0° ROM knee ), participants laid prone by pushing their trunk with the hands to the lounger (Figure 1B).…”

“…Each test consisted of five discrete movements (two submaximal, three with maximal effort) at 15°/s (only Hecc because it represents the NHE target movement speed), 30°/s and 150°/s, respectively 20‐22 . The last three repetitions were selected for further analysis.…”

“…For each testing condition, the trial with the highest gravity‐corrected peak moment was used for statistical analyses. For each angular velocity, the dynamic control ratio at the equilibrium point (DCRe) with the highest moment (each combination of the three flexor and extensor movements) was identified 21,22 . Peak power was calculated as product of actual camera‐based angular velocity and the moment value at time of peak power 17 .…”

“…Prospective studies dealing with the prevention and prognosis of sprint‐related injuries should provide evidence about the practicability and suitability of DCRe moments and angles 10,21,22,27 . Although hamstring injuries appear as knee muscle injury, the hamstring's biarticular nature renders hip joint mechanics essentially 4 .…”