The Acute Response of the Immune System to Tennis Drills in Adolescent Athletes

Article excerpt

Key words: cytokine, lymphocyte, neutrophil, saliva

Many components of the immune system exhibit change after intensive and prolonged exertion, including neutrophilia (high blood neutrophil counts), lymphopenia (low blood lymphocyte counts), decrease in natural killer cell cytotoxic activity, decrease in mitogen-induced lymphocyte proliferation (a measure of T cell function), increase in plasma concentrations of pro- and anti-inflammatory cytokines, for example, interleukin-6 (IL-6), interleukin-l0 (IL-10), and interleukin-1 receptor antagonist (IL-ira), decrease in ex vivo production of cytokines in response to mitogens, and decrease in nasal and salivary IgA concentration (see reviews by Gabriel & Kindermann, 1997; Mackinnon, 1999; Nieman, 1997; Nieman & Nehlsen-Gannarella, 1994). Depending on the immune measure, these changes take from 3 hr to 3 days to return to pre-exercise levels. Together, these data suggest that the immune system is suppressed and stressed, albeit transiently, following prolonged endurance exercise.

Whether these acute immune changes occur following extended bouts of sports drills, play, or competition is largely unknown (Karpovich, 1935; Oyster, 1980; Tharp, 1991; Wake, Graham, & McGrath, 1953). Nearly all acute exercise immunology studies have measured responses to cycling, running, swimming, rowing, cross-country skiing, and other modes of endurance exercise (Nieman, 1997). The response of the immune system to 1-3 hr of endurance exercise may differ from sports participation that incorporates an element of play, a discontinuous mixture of aerobic and anaerobic exertion, and lower postexercise blood concentrations of stress hormones (Bishop, Blannin, Robson, Walsh, & Gleeson, 1999).

Osterback & Qvarnberg (1987) reported that the incidence of respiratory tract infections was not elevated in young participants actively engaged in sports compared to controls. These data imply that youth can participate in sports for several hours daily without negative changes in immunosurveillance. Few data are currently available on exercise-induced changes in immune function among adolescents, which in general appears similar to adults (Boas et al., 1996; Tharp, 1991; Wolach et al., 1998).

In this study, the response of the immune system to a 2-hr intensive bout of tennis drills was measured in adolescent male and female athletes. We hypothesized that perturbations in immunity following intensive tennis drills would be of lower magnitude than previously measured in response to continuous, endurance exercise (Bishop et al., 1999; Nieman & Pedersen, 1999). Participants ingested carbohydrate beverages during the tennis drills according recommendations from sports nutrition professionals. Previous research has shown that carbohydrate compared to placebo ingestion has little or no influence on the immune response to sports drills (Bishop et al., 1999; Nieman et al., 1999).

Methods

Participants

Participants included 10 male and 10 female elite teenage tennis athletes (age range: 14-18 years) from the Van Der Meer World Class Tennis Training Center in Hilton Head, South Carolina. Informed consent was obtained from each participant, and the experimental procedures were in accordance with the policy statements of the institutional review board of Appalachian State University. The athletes reported an estimate of weekly exercise training duration in a questionnaire. Maximal aerobic power and heart rate were measured during a graded cycle ergometer protocol (Storer, Davis, & Caiozzo, 1990), using the MedGraphics CPX Express metabolic system (MedGraphics Corporation, St. Paul, MN) and chest heart rate monitors (Polar Electro Inc., Woodbury, NY). Body composition was estimated from seven skinfolds using the equations of Jackson & Pollock (1985).

Blood Sampling and Exercise Paradigm

The athletes reported to the tennis facility at 6:30 a. …