Anterior Cruciate Ligament Stress In The Golf Swing: Frontal Plane Knee Moments On The Target Side Limb.

Abstract

Frontal plane knee moments (FPKM) have been shown to be an important factor in the development and progression of knee injury and disease. Specifically, the external knee valgus moment has been identified as a risk factor for ACL injury. It is most likely the case that loads experienced by the knee during the golf swing are not large enough to make golf a risk factor for acute knee injury. However, golf swing loads may create small microtraumas to knee's soft tissues with each swing that could build up over time and result in significant macrotraumas. Since foot position can have an effect on the FPKM during gait, quantifying these loads in two different foot positions during the golf swing may provide further information about the relative stresses on the knee. PURPOSE: To quantify the FPKM during the golf swing in two different front foot set-up positions and to compare these loads to those in other sporting activities. METHODS: Participants were seven healthy golfers (5M, 21.3±3.1 years) who were all members of the University's Golf Team. Each participant performed five golf swings with the lead foot straight (STR) and with the lead foot externally rotated (EXT) while kinetic and kinematic data were collected. These data were used to calculate the FPKM. RESULTS: All subjects had a peak external knee valgus moment just prior to ball contact whose magnitude did not change with external rotation of the foot at set up (STR = 0.70 Nm/kg±0.12, EXT = 0.80 Nm/kg±0.19, p>0.05). Surprisingly, these loads are of similar magnitude to those calculated during a jump landing task (0.74±0.12Nm/kg) and during a side-step cutting maneuver (1.2±0.4Nm/kg) for female athletes who either went on to tear their ACL or were considered to be at high risk for ACL injury. CONCLUSIONS: Although generally considered a docile sport, the golf swing creates loads on the knee that are of similar magnitudes as jump landing and cutting. Sports that require jumping and cutting have an unpredictability factor that is not present in golf; however, the repeated nature of the golf swing during practice and play may lead to microtraumas that could build up over time and lead to knee injury/disease. This also may have implications in creating exercises and/or swing modifications to reduce the stress on the soft tissues of the knee during golf.