The 3 Areas of Swim Injuries: Research & Stats – Part I
As true to most sports, the healthiest and most injury avoidant athletes tend to excel throughout their careers. Swimming was officially identified as an overuse sport due to excessive repetitive and forceful shoulder revolutions, back hyperextensions, and knee extensions. Additionally, Dr. Rodeo exemplifies for USA Swimming by illustrating that a typical swimmer can reach up to 2 million shoulder revolutions in one season. Since this is such a broad topic, we will split the injury series into 4 pieces. We will focus on the research and statistics behind injuries in the 1st part, followed by a separate break-down of the main areas with advice on how to prevent and treat certain injuries.
In recent years, the sport of swimming has evolved precipitously due to increased competitiveness and improved ability of being able to apply new methods to improve swimming performance. Consequently, pain and injuries caused by competitive swimming have received large attention. Although swimming is often seen as a “low-impact” sport, a recent study classified it as a “high-overuse” sport, ranked second behind tennis. Current and past injury history was evaluated in over 1,600 athletic pediatric patients between 5-17 years participating in over thirty sports. If injuries were found to occur in at least 65%, the sport was categorized as “high-overuse.” Among swimmers, 83.6% of those who completed the study were considered to suffer from overuse injuries (Stracciolini, Casciano, Levey Friedman, Meehan III, & Michelo, 2015).
In swimming, the most common area of pain or irritation is located around the shoulder, followed by the knees and the back. These injuries may result in swimmers modify training intensity and volume, which in turn can affect their future performance. Two variables strongly correlate with shoulder pain in swimmers: 1) hours of training and 2) volume in yards or meters (Tate, Turner, Knab, Jorgensen, Strittmatter, & Michener, 2012; Harrington, Meisel, & Tate, 2014). In a cross-sectional study, Tate and colleagues (2012) found shoulder pain and disability occurring in 18-23% of 236 female swimmers across four different age groups. The most common symptoms for children below age 12 are reduced shoulder flexibility with latissimus dorsi tightness and reduced strength in the middle trapezius. Swimmers above age 12 showed symptoms of diminished core endurance and tightness in pectoralis minor. In fact, it is likely that shoulder symptomatic swimmers have shorter pectoralis minor muscle than asymptomatic swimmers (Harrington, Meisel, & Tate, 2014).
In another study, 80 Australian elite swimmers aged 13-25 completed 23 clinical tests, of which 53 swimmers underwent an additional MRI examination: 91% of the swimmers reported shoulder pain; 54% unilateral and 37% bilateral pain. During activity, 80% reported pain and 70% specified the pain occurring during overhead activity. Along with the pain, shoulder stiffness was seen in 68% of the swimmers. MRI findings show that supraspinatus tendon thickness is correlated with the level of training (P < .0001), years in training, and hours per week in training (P < .01). The risk for tendinopathy doubles if swimmers exceed 15 swimming hours per week, which is not uncommon in the world of swimming. Joint laxity and impingement are also correlated with swimming, but there are no current correlation showing that repetitive swimming increases joint laxity (Sain, et al., 2010). All swimmers who showed tendon thickness correlated strongly with impingement pain and supraspinatus tendinopathy (P < .00001), which occurred in 69% of the swimmers who completed the MRI screening, and each swimmer had a positive impingement sign.
The second most prevalent injury among swimmers is knee pain. Powerful and repetitive knee extensions from flutter- and dolphin kicking in combination with turns have a traumatic effect on the patellafemoral joint, in which the quadriceps are being overworked (Rodeo, 1999). Additionally, breaststrokers put tremendous pressure on the medial compartments of their knees during the kick phase (Vizsolyi, et al., 1987). The forceful long-lever adduction of the legs puts an enormous torque on the knee, as covered in our previous article. If the joint is not sufficiently strong and stable, the risk of injury increases. In a controlled cross-sectional study, 13 swimmers who were 14-15 years old underwent MRI scans. Out of the 26 knees examined, 69.2% revealed one or more abnormalities , compared to a control group where 32.1% of the knees showed one or more abnormalities, making knee abnormality frequency statistically significant (p=0.013) (Soder, Mizerkowski, Petkowicz, & Bldisserotto, 2012).
The Lower Back
The lower back is another frequently reported pain area for swimmers. A fairly recent study shows that lumbar disc degeneration is the plausible explanation (Kaneoka, et al., 2007). Fifty-six elite Japanese swimmers, ages 18-24 years underwent MRI scans. This study shows that there is a significant difference among swimmers who are exposed to higher volume of swimming and more years of training. To extrapolate, swimmers were categorized into a high-load vs. low-load group, as years of training, and training hours per week are most strongly correlated with low back pain. Lumbar degeneration was found in 68% of high-load swimmers and 29% of low-load swimmer, which is significantly higher (p= .021).
Injury for an athlete can be devastating and have damaging effect on the psyche and return to the sport. Athletes cope differently with their injuries from one another and will have contrasting severity on their careers. Recently, Mahler (2015) introduced an epidemiological 35-year old study supporting a strong hypothesis that injury prevention contributes to performance improvement. Prevention of injury is therefore necessary in order for an athlete to maintain their health in combination with intense and consistent periods of training. To prevent injuries for youth swimmers, reported recommendations of exercises for 11-year old swimmers should center their attention towards, but what remains unclear is if shoulder pain and disability is reversible without manipulating swimming volume or hours. No comprehensive or applied exercise programs exist to the public today where the effectiveness of the program is evaluated.
Until I did my master’s project and found trends and significant changes to modified functional movement screens (FMS) and pain reduction. My intervention is innovative as it takes fundamental prevention tactics from professionals into an applied form (Cools, Johansson, Borms, & Maenhout, 2015); Injury Prevention Programme, 2010; McGill, 1998; (Nichols, 2015); Riewald & Rodeo, 2015; Salo & Riewald, 2008; Wanivenhaus, Fox, Chaudhury, & Rodeo, 2012). The purpose of this project was to examine how an age- and sport specific 12-week exercise program affects functional movement and impingement scores in young competitive swimmers.
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