BRINGING SCIENCE TO TREATMENT

Row, row, row the boat – the consequences of repetitive strain in rowers

Tracy Ward considers the biomechanical and physical aspects of rowing and their contribution to upper extremity injuries and explores injury prevention strategies, including targeted strength and conditioning.

2016 Rio Olympics – Rowers from Australia compete. REUTERS/Carlos Barria

Rowing is a repetitive, weight-supported sport where the high training volumes are similar to cycling, kayaking, and swimming(1). Despite being non-contact and low-impact, rowers are still subject to significant and frequent injuries. Overuse injuries are particularly common due to the high stroke count from repeated training sessions, e.g., 14 to 18 sessions per week, amounting to up to 23 hours in total(2). In the standard 2000m race, rowers typically perform 210 to 230 strokes within approximately five to eight minutes(3).

Rib-stress injuries (RSIs) affect around 10% of rowers and cause the greatest time lost from on-water training(2). Depending on the severity of the injury, athletes may require up to six weeks off from training. Whether a reflection of overtraining or problems with technique, it seems that RSIs may be a precursor to future injuries. Therefore a strategic injury prevention program that reduces RSIs may also minimize other injury rates, improve retention, and enhance overall performance.

Mechanism of injury

Continuous and excessive loading of the ribs causes RSIs. During the rowing stroke, the serratus anterior pulls superiorly and laterally, while the external obliques exert a pull in the opposite direction – inferiorly and medially (see figure 1). Both muscles attach to the same area on the ribs. Because the rib bones have a small cross-sectional area, forces pulling in opposite directions can elicit a bone stress reaction. With continued training, the bone doesn’t have enough time to remodel following the repetitive micro-damage, and a stress fracture may result(2). The sixth and ninth ribs are the most vulnerable to RSIs.

Figure 1: Direction of pull during the rowing stroke

The total time spent on ergometer training, heavy strength training, and core stability training all directly influence the incidence of RSIs(4). These injuries are more prevalent among elite rowers where training volumes are excessive or progressed too quickly. Low bone mineral density and relative energy deficiency in sport (the physiological result of inadequate calorie intake compared to expenditure) are particular risk factors for elite rowers who try to maintain a set bodyweight while completing intense endurance training.

Additional risk factors for RSI include:

Intrinsic:

  • Muscle imbalances
  • Poor trunk strength & endurance
  • Reduced thoracic mobility

Extrinsic:

  • Poor row technique & stroke mechanics
  • Equipment problems
  • Excessive training loads

Muscle imbalances, asymmetries, or limitations in the range of motion impact performance and contribute to injury risk. Rowers often demonstrate significant asymmetry in their erector spinae muscles and occasionally in their hips and ankles(5). Instances of limited thoracic rotation place further stress on the lumbar spine and alter scapular motion.

During the stroke, rowers transmit significant power through the entire kinetic chain. In the propulsive phase, the legs generate the force which travels through the trunk and arms to the oar. Insufficient strength within the system alters the force transfer. The intensity and volume of training can also cause levels of fatigue that compromise technique. As rowers tire, they may compensate with increased movement in the spine. Increased spinal motion causes a shift in the force transfer from the lower body to the upper body, resulting in cumulative stress to the spine and ribcage. Therefore, a focused strengthening program to address muscle asymmetry, weakness, and fatigue is key to avoiding a stress injury.

Strengthening program

Strength training is essential to develop the muscles and movements required for rowing while also enhancing performance. Strong muscles absorb forces protecting the spine and rib cage(6). Since RSIs result from overuse, design a program to build strength and power without high repetitions.

A strength training program should increase thoracic spine mobility, shoulder girdle strength, and scapular movement. These components enable better biomechanical function and absorption of forces. Compound exercises are efficient ways to develop most of the upper body muscles. These movements mimic the transfer of forces through the trunk to the hands as in the rowing stroke. Such exercises could include the overhead push press and standing barbell row (6). Compound exercises should be programmed in 3-5 sets of 1-5 repetitions to allow maximal strength and power production with a long rest period of 2-4 minutes (1).

Isolated upper body exercises strengthen specific muscle groups and target those underdeveloped in rowing, such as the shoulder lateral rotators, retractors, depressors, pectorals, triceps, and anterior deltoids (see box 1)(7). Exercises to strengthen these muscles include dumbbell rows, shoulder raises, push-ups, and pull-ups. Perform these in 2-4 sets of 6-10 repetitions with a rest period of 1-3 minutes (1).


Box 1: Targeted sample exercises to strengthen rowing muscles

Thoracic mobility exercises consist of:

  • Spine twists
  • Arm openings
  • Side bends
  • Thoracic extension over a foam roller.

Tspine video

Scapular stability and strength exercises consist of:

  • Y, W, T movements
  • Dumb waiters
  • Seated rows

Shoulder girdle video

Y,W,T: When performing these movements, maintain scapular depression and retraction throughout each. Perform initially in prone on the floor, then progress to a standing hip hinge position to incorporate further core stability.

Dumb waiters: Maintain scapular depression and protraction, while rotating the shoulders. Maintain an upright posture with a neutral trunk position and neutral ribcage position.


 Strength and conditioning considerations

While rehabilitation conditioning for RSIs targets the upper body and trunk, lower body strength training remains important. Train the legs to coordinate the entire kinetic chain and prevent further overload to the trunk and upper body. Hinge-based exercises develop lumbopelvic coordination, which is vital in rowing(7). Front squats and hex-bar deadlifts are biomechanically similar to rowing. Hex-bar deadlifts are preferable over traditional deadlifts as they reduce the shear on the spine and maintain a more upright trunk position (6).

Start power training at the end-stage of rehabilitation after the athlete builds adequate strength to safely generate the desired propulsive forces. These exercises should focus on developing rapid concentric accelerations and could include medicine ball slams, high box jumps, and kettlebell swings (6). Utilize low repetitions to focus on maximal power output without fatigue.

Summary

  • Rowing consists of repetitive movements and requires both strength and endurance.
  • The repetitive nature of the sport frequently causes overuse injuries.
  • Rib stress injuries account for only 10% of rowing injuries but result in the most time lost from on-water training and may be a precursor to a later, more serious, injury.
  • Rib stress injuries occur due to an accumulation of bone micro-damage from repetitive loading.
  • Managing the load transfer from the legs through the trunk to the upper body helps prevent RSIs, since any break in the kinetic chain overloads the region and can result in injury.
  • Thoracic mobility and scapular motion exercises are key for initiating RSI rehabilitation.
  • Rehabilitation should then progress to compound, upper limb, lower limb, and power elements.

References

  1. NSCA. 2020; 42(3): 6-21.
  2. BJSM. 2016; 50: 266-269.
  3. Int J Sports Med. 1993; 14(Suppl 1): S3-10.
  4. BJSM. 2010; 44: 207-214.
  5. J Sport Sciences. 2011; 19(7): 521-526.
  6. NSCA. 2020; 7(2): 6-17.
  7. NSCA. 2020; 7(1): 6-17.

 

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