When a swimmer explodes off the starting blocks, each muscle needs to be firing in the proper sequence with full mobility to perform at the top level. Low back pain (LBP) can greatly hinder both performance and mobility. Although not as common as shoulder injuries, studies report low back injuries in 16% of elite swimmers,1 while other studies have reported much higher rates, ranging from 77%-87% in both high load and recreational swimmers.2 Low back pain affects swimmers of all ages, from the novice to elite level. This article will take you through a brief review of the anatomy and function of the back, causes and risk factors for LBP, and finally prevention and management strategies.
Anatomy and Function of the Lumbar Spine
Our spine is composed of a vertebral column (the bones) made up of individual vertebrae separated by soft, flexible intervertebral discs about ½ inch thick, which help absorb the load applied to the spine. In the center of the vertebra is the vertebral canal, which houses the spinal cord (Figure 1). Nerve roots exit through openings in the canal to supply both motor (movement, strength) and sensation throughout the body. The spine is also broken down into four regions: cervical, thoracic, lumbar, and sacrum (Figure 2), with our primary focus today being on the lumbar spine (Figure 2). Shown in the figures, the lumbar spine has a small, natural forward C-shaped curve, which helps dissipate the load on the spine.3
The muscles of the spine play an important role in movement, posture, stabilization, and shock absorption. A complex coordination of movements is needed to move the spine, and this is especially important for swimmers. Discussing each specific muscle is out of the scope of this article, but the muscles of the lumbar spine can be broadly categorized by their function: extension, flexion, rotation, and side bending. Extensors bend the spine backwards and keep the spine upright. Flexor muscles, which include the abdominal muscles, bend the spine forwards. If the abs are weak, that natural lordosis of the spine can be exaggerated, leading to excessive loading and low back pain.
Why do swimmers get low back pain?
In some studies, recreational swimming (i.e., swimming twice a week) can play a protective role in developing low back pain.5 This protective factor is not seen in competitive swimmers. Swimmers take the body into extreme ranges of motion in a repetitive manner and a powerful stroke requires positioning the body in unusual anatomic positions to maximize force production. If a swimmer’s form lacks sound biomechanics, he or she runs the risk of a musculoskeletal injury. For example, additional torsional (rotational) strain is seen when the body does not roll as a whole unit, resulting in abnormal loading at the point in the spine where the rolling stops.6 The low back can also be abnormally stressed if a swimmer demonstrates poor head and body position in the water.
In our discussion of low back pain, the butterfly and breaststroke deserve special attention due to their greater load and stress on the low back. In fact, the irritation seen in the facet joints have historically been referred to as “butterfly back syndrome.”7 The power and range needed in the kick for butterfly and breaststroke is dependent on adequate mobility of the lumbosacral (lower back) joints as well as hip, knee, and ankle flexibility. Specifically, with the butterfly stoke, repetitive flexion and extension of the trunk can, if the pelvis is tilted too far anteriorly (due to tight hip flexors, for example), excessively compress the facet joints in the vertebra. If this compression continues over time, the joint can become inflamed and lead to reflexive back spasms and pain.
Risk factors which have been shown to contribute to low back pain in swimmers are detailed in the table below.6.9
|Biomechanical or Training Error||Effects|
|Poor body roll||Leads to increased torsional/rotational strain on low back|
|Tight hip flexors||Leads to further hyperextension of the lumbar spine and increased anterior pelvic tilt (forward tipped pelvis)|
|Poor head and body position in the water||Leads to increased stress and loading on lumbar vertebrae|
|Sudden increase in training volume||Abrupt increases in work load can lead to excessive stress on the spine and increase risk for stress fractures. The increased fatigue from overtraining can also lead to poor form and subsequent musculoskeletal injury|
|Aggressive weight training||Practicing poor form with weight training and/or using too heavy of weights can be harmful to the spine|
|Overuse of “devices”||Excessive use of kickboards, fins, pull-buoys, hand-paddles, and zoomers can expose the back to repeated hyperextension differently than the open kinetic chain of regular swimming|
Prevention and Treatment of Low Back Pain
To avoid a nagging injury like low back pain, swimmers should take a preventative approach. A thorough assessment of mobility of the spine, hips, pelvis, and arms is essential. Correction of muscle imbalances (such as tight hip flexors, weak glutes and core), optimization of pelvic and joint mobility both in static (without movement) and dynamic (with movement) conditions should be addressed prior to ramping up training. Practicing proper form with the guidance of a coach or instructor will not only improve performance but also protect from musculoskeletal injuries including those of the low back. This is especially important in the breaststroke and butterfly, the swimming styles with the greatest incidence of LBP.10 For a swimmer who has a history of lower back pain or troubles, that athlete should be consistent with spinal stabilization exercises, practice sound biomechanics, and avoid sudden increases in training volume.
If a swimmer develops new low back pain, he or she should ideally be evaluated by a physician, especially if it persists and the swimmer is without a history of low back pain. Once a diagnosis has been reached, he or she may need to take a drastic reduction in training and focus on rehabilitation, which will include spinal stabilization exercises (i.e, core stability exercises) to prevent atrophy (or wasting) of the muscles surrounding the spine.11 If a spondylolysis (fracture) occurs, the swimmer may need a longer duration of modified activity (3-6 months) and a lumbar corset for better stabilization.12
Below are some excellent core strengthening and stretching exercises to help prevent low back pain and optimize performance in the water.
Hip Flexor Stretch
SB Streamline Crunches
MB Russian Twists
DB SLDL -2- Press
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About the Author:
Emily Kraus, MD
MD / Sports Medicine Specialist
Emily is a BridgeAthletic performance team contributor where she focuses on topics that are at the forefront of athletics and medicine. She is the incoming Stanford non-operative sports medicine fellow in Physical Medicine and Rehabilitation. Emily has provided medical coverage for events such as the USATF National Track and Field Championships and is the research coordinator for a multi-center study focused on prevention of stress fractures in division I collegiate runners. Emily has finished six marathons, recently ran (and won) her first 50km trail ultramarathon, and placed 56th female in the 2016 Boston Marathon. Emily is passionate about injury prevention, running biomechanics, and the promotion of health and wellness.
Courtesy of BridgeAthletic, a SwimSwam partner.