Risk Factors for Collegiate Swimmers Hospitalized With Exertional Rhabdomyolysis

To identify midseason risk factors for symptomatic exertional rhabdomyolysis (sER) in swimmers after a novel upper body workout.

Retrospective (1) survey and (2) analyses of observational laboratory data conducted over a 16-week training period, 2 months before sER.

Midwest University.

Thirty-four collegiate swimmers.

(1) Motivation, symptoms, and supplements for survey variables. (2) Changes (midseason minus preseason) in body composition, blood pressure (BP), urinary measures, and protein shake ingestion for laboratory variables.

Swimmers were categorized in hospitalized (H), treated and released from hospital (RH), and nonhospitalized (NH) groups for analyses.

(1) Six swimmers were in the H group (17.6%; 3 male/3 female) and 7 in the RH group (20.6%; 3 male/4 female). Nonsignificant trend toward H swimmers relating more upper body soreness (≥9/10) than RH (8/10) and NH (6/10) swimmers (P > 0.05) while reporting "felt bad and workout went poorly" (P = 0.009). H and RH swimmers reported more arm locking during the workout (P = 0.04) and brown urine after arm competition compared with NH-group swimmers (P = 0.03). (2) Increases in right systolic (P = 0.01) and left diastolic (P = 0.02) BP, with trends toward decreased left arm lean mass (P = 0.06) in H compared with RH and NH swimmers. Female H swimmers had more acidic urine (pH = 5.50 vs 6.9; P = 0.004), less volume, and higher specific gravity than RH + NH swimmers. All H swimmers regularly ingested protein shakes after workouts.

Risk factors for sER included exceptional motivation, extreme soreness, increased resting BP, acidic urine (females), and regular ingestion of protein shakes.