Summary

Although often considered a low-impact form of physical activity, advanced biomechanical motion analysis indicates that rowing exercise may increase risk of hip impingement through elevated hip flexion paired with diminishing row technique when training to fatigue.

Abstract

Background

Rowing ergometers have gained popularity for row training and as purportedly low-impact means of improving general fitness. However, previous studies have shown high rates of acute and overuse injuries of the hip and lumbar spine.

Purpose

Utilize 3D motion capture paired with clinical and coaching assessments to (1) determine if ergometer-based rowing results in hip flexion (HF) and internal rotation (HIR) associated with elevated risk of hip injury; (2) determine the impact of fatigue on hip range of motion (ROM), pull force, and row form; and (3) characterize the prevalence of hip pain/disfunction in recreational rowers.

Methods

Seventeen healthy amateur rowers (m=8, F=9; age=38±9.1 years, VO2max=44.4±7.8 ml·kg·min-1) volunteered to participate in this investigation. Following a standardized warmup, each subject performed a maximal effort 2000-meter row on an ergometer equipped with a load cell (Futek®) to record pull force. Kinematics were recorded using a 12-camera motion capture system (Vicon®). Data was recorded at the 200m, 600m, 1000m, 1400m, and 1800m distances. Risk thresholds were set at 90° of HF and 10° of HIR. Three professional rowing instructors (average 11.5 years rowing/coaching) evaluated row technique at the 200m and 1800m distances using a 1-4 rating scale (1, poor technique – 4, excellent technique) for the catch, drive, finish, and overall technique. Prior to beginning the bout, rowers completed an International Hip Outcome Tool (iHOT-12, VAS: 0 pain/disfunction – 100 no pain/no disfunction) survey. A mixed-model ANOVA repeated on row distance followed by a Tukey’s post-hoc test for pairwise comparisons was used to compare biomechanical assessments during the bout. A Mann-Whitney test for non-parametric data was used to compare rowing form scores between the 200m and 1800m distances. Type-I error was set at a=0.05 for all analyses.

Results

No effect of row distance was observed for either HF or HIR. For HF, the group significantly exceeded the 90° risk threshold throughout the 2000m row (p<0.001, 111.0±5.3°) with all patients above the threshold throughout the rowing bout. For HIR, the group did not differ from the 10° risk threshold. Following the 200m measurement (8.2±0.4 N/kg), peak force was observed to significantly decrease at the 600m (7.4±0.4 N/kg, p=0.004) and 1000m (7.5±0.4 N/kg, p=0.005) measurements followed by a subsequent increase at the 1800m measurement (8.4±0.5 N/kg) to a value similar to the 200m measurement. Rowing form decreased from the 200m to 1800m measurement (overall; 200m, 2.2±0.3 | 1800m, 1.9±0.2; p=0.012). The mean iHOT-12 score for the group was 89.5±7.6 with more than 50% of the participants reporting some degree of discomfort/disfunction (<100).

Conclusion

While generally considered a low-impact exercise, recent studies have illuminated the risk of hip injury from rowing. Repetitive high degrees of hip flexion coupled with moderate pull forces and declining form with fatigue may place rowers at an increased risk of hip overuse injuries or FAI. Therefore, caution should be exercised when considering performing or prescribing repeated bouts of high intensity or fatiguing rowing. These findings may also assist in refining the concept of “low-impact” as it pertains to joint-specific injury risk.