Abstract
Study Design: Reliability and case-control injury study.
Objectives: To establish test re-test reliability of a novel apparatus measuring knee flexor strength during various hamstring exercises; to investigate whether these measures detect between-leg differences in males with and without history of unilateral hamstring strain injury (HSI).
Background: Knee flexor strength is a key variable when dealing with HSI and methodologies of objective measurement are often limited to single exercises.
Methods: Twenty males without and ten males with previous unilateral HSI participated. Isometric knee flexor strength and peak rate of force development (RFD) at 0/0, 45/45 and 90/90 degrees of hip/knee flexion were measured, as well as force impulse during bilateral and unilateral variations of an eccentric slider and hamstring bridge, using a novel apparatus. Intraclass correlation coefficient (ICC), typical error (TE) and typical error as a co-efficient of variation (%TE) were calculated for all measures. The magnitude of between-leg differences within each group were calculated using estimates of effect sizes reported as Cohen’s d with a ± 90% confidence interval (CI).
Results: Moderate to high test re-test reliability was observed for isometric knee flexor strength (ICC = 0.87 to 0.92) and peak RFD (ICC = 0.87 to 0.95) across three positions and mean force impulse during the eccentric slider (ICC = 0.83 to 0.90). In those with prior HSI, large deficits were seen in the previously injured leg compared to the contralateral uninjured leg for mean force impulse during the unilateral eccentric slider (d = -1.09, 90% CI = -0.20 to -1.97), isometric strength at 0/0 (d = -1.06, 90% CI = -0.18 to -1.93) and 45/45 (d = -0.88, 90% CI = -0.02 to -1.74) and peak RFD at 45/45 (d = -0.88, 90% CI = -0.02 to -1.74).
Conclusions: The novel apparatus provides a reliable measure of isometric knee flexor strength, peak RFD and force impulse during an eccentric slider, with deficits seen in previously injured hamstrings for these measures.
Objectives: To establish test re-test reliability of a novel apparatus measuring knee flexor strength during various hamstring exercises; to investigate whether these measures detect between-leg differences in males with and without history of unilateral hamstring strain injury (HSI).
Background: Knee flexor strength is a key variable when dealing with HSI and methodologies of objective measurement are often limited to single exercises.
Methods: Twenty males without and ten males with previous unilateral HSI participated. Isometric knee flexor strength and peak rate of force development (RFD) at 0/0, 45/45 and 90/90 degrees of hip/knee flexion were measured, as well as force impulse during bilateral and unilateral variations of an eccentric slider and hamstring bridge, using a novel apparatus. Intraclass correlation coefficient (ICC), typical error (TE) and typical error as a co-efficient of variation (%TE) were calculated for all measures. The magnitude of between-leg differences within each group were calculated using estimates of effect sizes reported as Cohen’s d with a ± 90% confidence interval (CI).
Results: Moderate to high test re-test reliability was observed for isometric knee flexor strength (ICC = 0.87 to 0.92) and peak RFD (ICC = 0.87 to 0.95) across three positions and mean force impulse during the eccentric slider (ICC = 0.83 to 0.90). In those with prior HSI, large deficits were seen in the previously injured leg compared to the contralateral uninjured leg for mean force impulse during the unilateral eccentric slider (d = -1.09, 90% CI = -0.20 to -1.97), isometric strength at 0/0 (d = -1.06, 90% CI = -0.18 to -1.93) and 45/45 (d = -0.88, 90% CI = -0.02 to -1.74) and peak RFD at 45/45 (d = -0.88, 90% CI = -0.02 to -1.74).
Conclusions: The novel apparatus provides a reliable measure of isometric knee flexor strength, peak RFD and force impulse during an eccentric slider, with deficits seen in previously injured hamstrings for these measures.
| Original language | English |
|---|---|
| Number of pages | 25 |
| Journal | The Journal of Orthopaedic and Sports Physical Therapy |
| Volume | 48 |
| Issue number | 2 |
| Early online date | 1 Nov 2017 |
| DOIs | |
| Publication status | Published - Feb 2018 |
Keywords
- eccentric
- force impulse
- isometric
- muscle
- rate of force development
- Strain Injury
- knee flexor strength
- hamstring exercises