Angle-specific torque profiles of concentric and eccentric thigh muscle strength 20 years after anterior cruciate ligament injury.

Thigh muscle weakness prevails following anterior cruciate ligament (ACL) injury, as usually evaluated by peak concentric quadriceps strength. Assessment throughout the range of motion (ROM), and for antagonists may provide more comprehensive information. We evaluated angle-specific torque profiles and ratios of isokinetic thigh muscle strength in 70 individuals 23 ± 2 years post-ACL injury (44males, 46.9 ± 5.4 years); 33 treated with ACL-reconstruction (ACL-R), and 37 treated only with physiotherapy (ACL-PT), and 33 controls. Quadriceps and hamstrings torques for concentric/eccentric contractions (90°/s) and ratios between hamstrings/quadriceps strength (HQ) were compared between and within groups using inferential functional data methods. The injured ACL-R leg had lower concentric and eccentric quadriceps strength compared to non-injured leg throughout the ROM, and lower concentric (interval 70-79°) and eccentric (64-67°) quadriceps strength compared to controls. The injured ACL-PT leg showed lower eccentric quadriceps strength (53-77°) than non-injured leg and lower concentric (41-79°) and eccentric (52-81°) quadriceps and eccentric hamstrings (30-77°) strength than controls. There were no group differences for HQ-ratios. The injured ACL-R leg had higher HQ-ratio (34-37°) than non-injured leg. Angle-specific torque profiles revealed strength deficits, masked if using only peak values, and seem valuable for ACL-injury rehabilitation.

Seated postural neck and trunk reactions to sideways perturbations with or without a cognitive task.

Driving on irregular terrain will expose the driver to sideways mechanical shocks or perturbations that may cause musculoskeletal problems. How a cognitive task, imposed on the driver, affects seated postural reactions during perturbations is unknown. The aim of the present study was to investigate seated postural reactions in the neck and trunk among healthy adults exposed to sideways perturbations with or without a cognitive task. Twenty-three healthy male subjects aged 19-36 years, were seated on a chair mounted on a motion system and randomly exposed to 20 sideways perturbations (at two peak accelerations 5.1 or 13.2m/s(2)) in two conditions: counting backwards or not. Kinematics were recorded for upper body segments using inertial measurement units attached to the body and electromyography (EMG) was recorded for four muscles bilaterally in the neck and trunk. Angular displacements (head, neck, trunk and pelvis) in the frontal plane, and EMG amplitude (normalised to maximum voluntary contractions, MVC) were analysed. The cognitive task provoked significantly larger angular displacements of the head, neck and trunk and significantly increased EMG mean amplitudes in the upper neck during deceleration, although 10% of MVC was never exceeded. A cognitive task seems to affect musculoskeletal reactions when exposed to sideways perturbations in a seated position.

Anterior cruciate ligament injury about 20 years post-treatment: A kinematic analysis of one-leg hop.

Reduced dynamic knee stability, often evaluated with one-leg hops (OLHs), is reported after anterior cruciate ligament (ACL) injury. This may lead to long-standing altered movement patterns, which are less investigated. 3D kinematics during OLH were explored in 70 persons 23 ± 2 years after ACL injury; 33 were treated with physiotherapy in combination with ACL reconstruction (ACL(R)) and 37 with physiotherapy alone (ACL(PT)). Comparisons were made to 33 matched controls. We analyzed (a) maximal knee joint angles and range of motion (flexion, abduction, rotation); (b) medio-lateral position of the center of mass (COM) in relation to knee and ankle joint centers, during take-off and landing phases. Unlike controls, ACL-injured displayed leg asymmetries: less knee flexion and less internal rotation at take-off and landing and more lateral COM related to knee and ankle joint of the injured leg at landing. Compared to controls, ACL(R) had larger external rotation of the injured leg at landing. ACL(PT) showed less knee flexion and larger external rotation at take-off and landing, and larger knee abduction at Landing. COM was more medial in relation to the knee at take-off and less laterally placed relative to the ankle at landing. ACL injury results in long-term kinematic alterations during OLH, which are less evident for ACL(R).

Anterior cruciate ligament injury after more than 20 years. II. Concentric and eccentric knee muscle strength.

The long-term consequences on knee muscle strength some decades after rupture of the anterior cruciate ligament (ACL) are not established. The aims of our study were to examine peak torque more than 20 years after ACL injury and to compare their knee muscle strength to that of healthy controls. We tested 70 individuals with unilateral ACL injury 23 ± 2 years after injury, whereof 33 (21 men) were treated with physiotherapy in combination with ACL reconstruction (ACLR ) and 37 (23 men) with physiotherapy alone (ACLPT ). These were compared with 33 age- and gender-matched controls (21 men). A Kin-Com(®) dynamometer (90°/s) was used to measure peak torque in knee flexion and extension in both concentric and eccentric contractions. Knee extension peak torque, concentric and eccentric, was ∼10% lower for the injured leg compared with the non-injured leg for both ACLR (P < 0.001; P < 0.001) and ACLPT (P = 0.007; P = 0.002). The ACLPT group also showed reduced eccentric knee flexion torque of the injured leg (P = 0.008). The strength of the non-injured leg in both ACL groups was equal to that of controls. No difference was seen for those with no-or-low degree of knee osteoarthritis compared to those with moderate-to-high degree of osteoarthritis. ACL injury may lead to a persistent reduction of peak torque in the injured leg, which needs to be considered across the lifespan.

Anterior cruciate ligament injury after more than 20 years: I. Physical activity level and knee function.

Little is known about physical activity level and knee function including jump capacity and fear of movement/reinjury more than 20 years after injury of the anterior cruciate ligament (ACL). Seventy persons with unilateral ACL injury participated (23 ± 2 years post-injury): 33 treated with physiotherapy in combination with surgical reconstruction (ACLR ), and 37 treated with physiotherapy alone (ACLPT ). These were compared with 33 age- and gender-matched controls. Assessment included knee-specific and general physical activity level [Tegner activity scale, International Physical Activity Questionnaire (IPAQ)], knee function [Lysholm score, Knee injury and Osteoarthritis Outcome Score (KOOS)], jump capacity (one-leg hop, vertical jump, side hops), and fear of movement/reinjury [Tampa Scale for Kinesiophobia (TSK)]. Outcomes were related to degree of osteoarthritis (OA). ACL-injured had lower Lysholm, KOOS, and Tegner scores than controls (P < 0.001), while IPAQ score was similar. ACL-injured demonstrated inferior jump capacity in injured compared with noninjured leg (6-25%, P < 0.001-P = 0.010 in the different jumps), while noninjured leg had equal jump capacity as controls. ACL groups scored 33 ± 7 and 32 ± 7 of 68 on TSK. Lower scores on Lysholm and KOOS symptom were seen for persons with moderate-to-high OA than for no-or-low OA, while there were no differences for physical activity and jump capacity. Regardless of treatment, there are still negative knee-related effects of ACL injury more than 20 years later.