Intensified Training Period Increases Salivary IgA Responses But Does Not Affect the Severity of Upper Respiratory Tract Infection Symptoms in Prepuberal Rhythmic Gymnasts.

This study examined the effect of a 4-week intensified training (IT) period, followed by a 2-week tapering period (TP), on salivary immunoglobulin A (SIgA), salivary cortisol, and the severity of upper respiratory tract infection symptoms in 23 rhythmic gymnasts [12.1 (2.6) y; 143.9 (13.7) cm; 37.2 (9.4) kg]. Saliva sampling was conducted at pre- and post-IT, and post-TP (analyzed using enzyme-linked immunosorbent assay). The Wisconsin Upper Respiratory Symptom Survey (WURSS-21) questionnaire was completed daily to analyze the severity of upper respiratory tract infection symptoms. The session rating of the perceived exertion was used to determine the internal training load and the acute:chronic workload ratio. A higher SIgA concentration [SIgAabs (μg/mL); F = 7.6; P = .001] for post-IT [234 (104)] versus pre-IT [173 (91)], and post-TP [182 (70)], and a higher SIgA secretion rate [SIgArate (μg/min); F = 3.4; P = .04] for post-IT [69 (28)] versus pre-IT [55 (27)], and post-TP [58 (22)] were observed. No significant change was observed for cortisol (F = 0.81; P = .45) or for the severity of upper respiratory tract infection symptoms (χ2  = 2.81; P = .24). Internal training load was higher during IT (vs TP; effect size = 2.37). The acute:chronic workload for the IT weeks varied from 1.2 (0.3) to 1.4 (0.3). These results suggest that a 4-week IT may temporarily augment the oral mucosal immunity, and an acute:chronic workload of 1.2-1.4 seems to be a safe approach to periodized training loads in youth rhythmic gymnasts.