. Purpose: Based on the resistance-rpm relationship for cycling, which is not unlike the force-velocity relationship of muscle, it is hypothesized that the cadence which requires the minimal muscle activation will be progressively higher as power output increases. Methods: To test this hypothesis, subjects were instrumented with surface electrodes placed over seven muscles that were considered to be important during cycling. Measurements were made while subjects cycled at 100, 200, 300, and 400 W at each cadence: 50, 60, 80, 100, and 120 rpm. These power outputs represented effort which was up to 32% of peak power output for these subjects. Results: When all seven muscles were averaged together, there was a proportional increase in EMG amplitude each cadence as power increased. A second-order polynomial equation fit the EMG:cadence results very well (r 2 ϭ 0.87-0.996) for each power output. Optimal cadence (cadence with lowest amplitude of EMG for a given power output) increased with increases in power output: 57 Ϯ 3.1, 70 Ϯ 3.7, 86 Ϯ 7.6, and 99 Ϯ 4.0 rpm for 100, 200, 300, and 400 W, respectively. Conclusion: The results confirm that the level of muscle activation varies with cadence at a given power output. The minimum EMG amplitude occurs at a progressively higher cadence as power output increases. These results have implications for the sense of effort and preferential use of higher cadences as power output is increased.

Low back pain is a common musculoskeletal disorder affecting golfers, yet little is known of the specific mechanisms responsible for this injury. The aim of this study was to compare golf swing spinal motion in three movement planes between six male professional golfers with low back pain (age 29.2+/-6.4 years; height 1.79+/-0.04 m; body mass 78.2+/-12.2 kg; mean +/- s) and six without low back pain (age 32.7+/-4.8 years; height 1.75+/-0.03 m; body mass 85.8+/-10.9 kg) using a lightweight triaxial electrogoniometer. We found that golfers with low back pain tended to flex their spines more when addressing the ball and used significantly greater left side bending on the backswing. Golfers with low back pain also had less trunk rotation(obtained from a neutral posture), which resulted in a relative 'supramaximal' rotation of their spines when swinging. Pain-free golfers demonstrated over twice as much trunk flexion velocity on the downswing, which could relate to increased abdominal muscle activity in this group. This study is the first to show distinct differences in the swing mechanics between golfers with and without low back pain and provides valuable guidance for clinicians and teachers to improve technique to facilitate recovery from golf-related low back pain.

Abdominal muscle activity and muscle fatigue characteristics were quite similar between AC and CLBP subjects after repetitive golf swings. Despite this, it was clear that repetitive golf swings were aggravating some part of the musculoskeletal system in CLBP subjects, which resulted in increased pain in the low back area.

No abstract

Low back problems account for the largest proportion of injuries among amateur and professional golfers. However, there is little data on how the trunk or spine moves during a golf swing. Also, it may be that different golf clubs produce different trunk motion characteristics. The purpose of this study was to compare trunk range of motion (ROM) and velocity in three movement planes during the execution of a full golf swing using a driver and a 7-iron. Forty-four members of the Alberta Professional Golf Association volunteered to participate in this study. Trunk ROM and velocities in the sagittal, frontal, and transverse planes were measured using a triaxial electrogoniometer. Results showed that significantly more trunk flexion was required when setting up to hit the ball with the 7-iron compared to the driver, p < 0.05. During the swing, significantly greater maximum flexion and left-side-bend ROM occurred when using the 7-iron, p < 0.05. Maximum right-side-bending velocity during the golf swing was also significantly greater with a 7-iron. These findings suggest that differences in shaft length and ball positioning associated with the different clubs affects swing mechanics and trunk/spinal motion. In particular, the shorter club (7-iron) tended to place more emphasis on lateral trunk motion than did the driver. The results from this study may help clinicians better understand how the golf swing creates stress on the back as well as how club fitting may affect trunk motion characteristics.