Exercise-induced knee joint laxity in distance runners.

Abstract

The objectives of this study were to evaluate the effect of exercise on knee joint laxity. If exercise induced laxity is physiological, incorporation of this quality into a ligament replacement material would be indicated. Twenty recreational long distance runners average age 41 (range 24 to 50 yr) were tested before and immediately after 30 minutes of running. Using a computerized goniometer type instrument (Acufex KSS), knee flexion, axial tibial rotation and anterior-posterior tibial displacement were simultaneously recorded, while the runners underwent tests of static as well as dynamic knee joint laxity.At 30 degrees of knee flexion, a maximum increase of 16 per cent in mean total anterior-posterior laxity post-exercise was found. At the examination 30 minutes post-exercise, laxity at 30 degrees of knee flexion was still increased. However, laxity at 90 degrees of knee flexion had decreased to pre-exercise levels or below. Anterior tibial displacement, recorded during eccentric quadriceps activity (O to 90 degrees of knee flexion) with weights attached to the foot, showed a maximum of 18 per cent increase in total anteriorposterior laxity post-exercise. It is suggested that the laxity increase is caused in part by a true ligamentous laxity increase, and in part by a decreased resting tone of the fatigued muscles.

Repetitive jumping and sprinting until exhaustion alters hamstring reflex responses and tibial translation in males and females

“…It has been proposed that the extent of joint laxity may be associated with an increased risk to sustain an ACL injury . Several studies have shown that sports activities such as running or a regular workout in volleyball can increase anterior knee laxity . However, only a study performed by Kvist et al has compared TT in females and males after exhausting exercise and found an increase of this parameter in males.…”

“…29 Several studies have shown that sports activities such as running or a regular workout in volleyball can increase anterior knee laxity. 17,20,21,27 However, only a study performed by Kvist et al 21 has compared TT in females and males after exhausting exercise and found an increase of this parameter in males. Nevertheless, these studies measured anterior knee laxity while subjects were relaxed.…”

Changes in Fatigue, Multiplanar Knee Laxity, and Landing Biomechanics During Intermittent Exercise

“…15 As such, these increases are thought to result primarily from viscoelastic changes in joint structures rather than muscular fatigue. 15,19 However, as knee laxity continues to increase and remains elevated with increasing exercise duration, 12,15 the potential for higher-risk biomechanics may be compounded as muscular fatigue develops. [20][21][22] We are not aware of any studies in which researchers have examined relationships between concurrent changes in neuromuscular fatigue and knee laxity and lower extremity biomechanics during exercise that are consistent with the duration, intensity, and movement demands of sport activity.…”

Multiplanar Knee Laxity Increases during a 90-min Intermittent Exercise Protocol

“…ACL injury typically occurs during sports that involve sudden deceleration and change of direction (e.g., soccer, basketball, and football) (8). However, studies examining knee laxity changes during exercise have primarily focused on sagittal plane activities such as flexion/extension isokinetic contractions (24), stationary cycling (1), forward running (9,17,25,36), or a combination thereof (35). While some have incorporated limited cutting and landing activities into their submaximal running protocols (19,25) or examined changes during multidirectional running (6), only two have measured changes after sport practices (e.g., basketball [36] and cheerleading [22]).…”