Relationship Between Quadriceps Strength and Knee Joint Power During Jumping After ACLR

The Relationship of Open- and Closed-Kinetic-Chain Rate of Force Development With Jump Performance Following Anterior Cruciate Ligament Reconstruction

PURPOSE

To determine between-limbs differences in isometric rate of force development (RFD) measured during open- (OKC) and closed-kinetic-chain (CKC) strength testing and establish which method had the strongest relationship to single-leg vertical-jump performance and knee mechanics after anterior cruciate ligament (ACL) reconstruction.

METHODS

Subjects (n = 19) 1 to 5 years from ACL reconstruction performed isometric knee extensions (OKC), unilateral isometric midthigh pulls (CKC), and single-leg vertical jumps on the ACL-involved and -noninvolved limbs. Between-limbs differences were assessed using paired t tests, and the relationship between RFD, jump performance, and knee mechanics was assessed using correlation coefficients (r; P ≤ .05).

RESULTS

There were significant between-limbs differences in OKC RFD (P = .008, d = -0.69) but not CKC RFD. OKC RFD in the ACL-involved limb had a strong association with jump height (r = .64, P = .003), knee-joint power (r = .72, P < .001), and peak knee-flexion angle (r = .72, P = .001). CKC RFD in the ACL-involved limb had a strong association with jump height (r = .65, P = .004) and knee-joint power (r = .67, P = .002) but not peak knee-flexion angle (r = .40, P = .09).

CONCLUSIONS

While both OKC and CKC RFD were strongly related to jump performance and knee-joint power, OKC RFD was able to detect between-limbs RFD asymmetries and was strongly related to knee-joint kinematics. These findings indicate that isometric knee extension may be optimal for assessing RFD after ACL reconstruction.

Lower extremity joint angle, moment, and coordination throughout a double limb drop vertical jump in individuals with anterior cruciate ligament reconstruction

Individuals with anterior cruciate ligament reconstruction (ACLR) utilise different landing biomechanics between limbs, but previous analyses have not considered the continuous or simultaneous joint motion that occurs during landing and propulsion. The purpose of this study was to compare sagittal plane ankle/knee and knee/hip coordination patterns as well as ankle, knee, and hip angles and moments and vertical ground reaction force (vGRF) between the ACLR and uninjured limbs during landing and propulsion. Fifteen females and thirteen males performed a drop vertical jump from a 30 cm box placed half their height from force platforms. Coordination was compared using a modified vector coding technique and binning analysis. Kinematics and kinetics were time normalised for waveform analyses. Coordination was not different between limbs. The ACLR limb had smaller dorsiflexion angles from 11 to 16% of landing and 24 to 75% of landing and propulsion, knee flexion moments from 5 to 15% of landing, 20 to 31% of landing, and 35 to 91% of landing and propulsion, and vGRF from 92 to 94% of propulsion compared with the uninjured limb. The ACLR limb exhibited smaller dorsiflexion angles to potentially reduce the knee joint moment arm and mitigate the eccentric and concentric demands on the ACLR knee during landing and propulsion, respectively.

Mechanical energy flow analysis in athletes with and without anterior cruciate ligament reconstruction during single-leg drop landing

Techniques that reduce mechanical energy have been linked to lower chances of experiencing an Anterior Cruciate Ligament (ACL) injury. Although there is evidence that movement patterns are altered in athletes who have undergone Anterior Cruciate Ligament Reconstruction (ACLR), energy transfer mechanisms have not been examined. This study aimed to compare energy flow mechanisms during single-leg drop landing between athletes with and without history of ACLR. A total of 20 female athletes were included in this study. Ten participants underwent ACLR 12 months ago (mean age, 21.57 ± 0.41 years) and 10 were healthy controls (mean age, 20.89 ± 0.21 years). Participants executed the single-leg drop landing (SLL) maneuver by descending from a 30 cm wooden box and landing on the tested leg on an embedded force plate. Information collected during the SLL trials was refined using rigid-body analysis and inverse dynamics within Nexus software, ultimately allowing construction of skeletal models of the athletes. Ankle and knee mechanical energy expenditure (MEE) was higher in the control participants during landing. However, the result for the hip MEE demonstrated that MEE of the control group was significantly lower compared with the ACLR group, but MEE of the control subjects was higher as compared to ACLR group (p ˂ 0.05). Results suggest the avoidant use of the quadriceps muscle post ACLR leads to knee-avoidant mechanics and loss of knee joint power generation during a SLL task.