Associations of isokinetic knee steadiness with hop performance in patients with ACL deficiency
- 488 Downloads
Contrary to the ample data available regarding the functional significance of isokinetic knee strength in patients with anterior cruciate ligament deficiency (ACLD), much less is known about the functional significance of isokinetic knee steadiness. This cross-sectional study aimed to evaluate, in patients with ACLD, the independent impact of isokinetic quadriceps and hamstrings torque steadiness on single-leg hop performance.
Eighty-seven patients with unilateral ACLD participated. Patients performed isokinetic quadriceps and hamstrings steadiness and strength testing at 60°/s on an isokinetic dynamometer. Muscle steadiness and strength were represented by the wavelet-derived mean instantaneous frequency and peak value of the torque–time curves, respectively. To measure hop performance, patients performed a single-leg hop for distance and a 6-m single-leg hop for velocity.
One of two patients [n = 45 (51 %)] had a 10 % or greater difference in knee torque frequency levels between the ACLD and contralateral knees. In multivariable models adjusted for age, sex, knee pain, and knee strength, hamstrings steadiness was significantly related with hop velocity whilst quadriceps steadiness was significantly related with both hop distance and velocity. Variance decomposition analyses suggested that quadriceps steadiness was similar in importance to hamstrings strength on hop distance and velocity.
In patients with ACLD, isokinetic knee steadiness deficits were common and were independently associated with single-leg hop performance. Knee torque steadiness—a heretofore understudied variable—may prove a useful adjunct to conventional peak torque measurements by offering additional information to researchers and rehabilitation professionals about muscle performance and neuromuscular knee control.
Level of evidence
Prognostic studies, Level III.
KeywordsForce control Isokinetics Knee ACL deficiency Single-leg hop test
This project is grant funded by Singhealth Foundation start-up grant (SHF/FG476S/2010). We thank Tan Bee Yee, the head of the Department of Physiotherapy, Singapore General Hospital, for supporting this study; John Tan Wei-Ming for his assistance; Luke Perraton for his advice; and the orthopaedic surgeons from the Singapore General Hospital for allowing us access to their patients.
- 15.Daniel DM, Stone ML, Riehl B, Moore MR (1988) A measurement of lower limb function: the one-leg hop for distance. Am J Knee Surg 1(4):212–214Google Scholar
- 20.Grindem H, Logerstedt D, Eitzen I, Moksnes H, Axe MJ, Snyder-Mackler L, Engebretsen L, Risberg MA (2011) Single-legged hop tests as predictors of self-reported knee function in nonoperatively treated individuals with anterior cruciate ligament injury. Am J Sports Med 39(11):2347–2354PubMedCentralPubMedCrossRefGoogle Scholar
- 24.Hurd WJ, Axe MJ, Snyder-Mackler L (2008) A 10-year prospective trial of a patient management algorithm and screening examination for highly active individuals with anterior cruciate ligament injury: part 2, determinants of dynamic knee stability. Am J Sports Med 36(1):48–56PubMedCentralPubMedCrossRefGoogle Scholar
- 32.Lindeman RH, Merenda PF, Gold RZ (1980) Introduction to bivariate and multivariate analysis. Scott Foresman, GlenviewGoogle Scholar
- 41.Seidler-Dobrin RD, He J, Stelmach GE (1998) Coactivation to reduce variability in the elderly. Mot Control 2(4):314–330Google Scholar