Whatever the swimming specialty, swim training programs generally consist of high volume, which may shifts the heart rate (HR) autonomic control towards vagal predominance. Although it is accepted that an enhanced parasympathetic tone may improve performance on long distances, it is poorly known whether it may affect performance on short distances. PURPOSE. To evaluate resting autonomic tone and swimming performance on short and long distances in highly trained swimmers. METHODS. Two groups of national–level swimmers (all males, crawl specialists) were evaluated: short (S: 50-100 m; n=13; 24±3 yrs) and long (L: 1500 m; n=9; age 19±1 yrs) distance specialists. All swimmers belonged to the same team and were similar for training level. Beat-by-beat HR was recorded at rest in the morning, in supine position, by a HR monitor for 15 minutes. HR variability indexes were calculated from time (RMSSD, pNN50, indexes of vagal tone) and frequency (LF, Low Frequency and HF, High Frequency as absolute values and in normalized units (nu); LF/HF ratio, index of sympathovagal balance) domains. The anaerobic threshold was evaluated by an incremental swimming test with lactate measurements. RESULTS. The percentage of swimmers who showed resting bradycardia tended to be higher in L (78%) than in S (54%) group. HRV indexes did not significantly differ between groups: RMSSD 67±23 vs 66±11 ms, pNN50 40±17 vs 48±10%, LFnu 62.3±12.3 vs 54.4±14.8, HFnu 37.6±12.3 vs 45.6±14.8, LF/HF 2.1±1.9 vs 1.5±1.0 (S vs L group, respectively). In S group, 50 m best time correlated positively (p<0.05) with RMSSD (r=0.64), pNN50 (r=0.73) and absolute HF power (r=0.64), and negatively with LFnu (r=-0.56), but not with anaerobic threshold. On the contrary, in L group 1500 m did not correlate with RMSSD, pNN50 and absolute HF power (although negative trends were perceived), negatively correlated with absolute LF power (r=-0.65 p=0.05), positively correlated to LFnu (r=0.72, p=0.02), and tended to increase with anaerobic threshold. CONCLUSION. L swimmers were not more hypervagotonic than S swimmers, and such adaptation tended to be positively associated with anaerobic threshold. Conversely, high vagal tone appeared somehow detrimental on short swimming performance, as it negatively predicts performance on 50 m events, whereas anaerobic threshold did not.

EFFECTS OF AUTONOMIC TONE ON SHORT VERSUS LONG DISTANCE PERFORMANCES IN SWIMMERS / M.A. Maggioni, A. Veicsteinas, C. Ciapparelli, P. Castiglioni, G. Merati. ((Intervento presentato al 59. convegno American College of Sports Medicine Annual Meeting 2012 tenutosi a San Francisco, CA nel 2012.

EFFECTS OF AUTONOMIC TONE ON SHORT VERSUS LONG DISTANCE PERFORMANCES IN SWIMMERS

M.A. Maggioni;A. Veicsteinas;G Merati
2012-05

Abstract

Whatever the swimming specialty, swim training programs generally consist of high volume, which may shifts the heart rate (HR) autonomic control towards vagal predominance. Although it is accepted that an enhanced parasympathetic tone may improve performance on long distances, it is poorly known whether it may affect performance on short distances. PURPOSE. To evaluate resting autonomic tone and swimming performance on short and long distances in highly trained swimmers. METHODS. Two groups of national–level swimmers (all males, crawl specialists) were evaluated: short (S: 50-100 m; n=13; 24±3 yrs) and long (L: 1500 m; n=9; age 19±1 yrs) distance specialists. All swimmers belonged to the same team and were similar for training level. Beat-by-beat HR was recorded at rest in the morning, in supine position, by a HR monitor for 15 minutes. HR variability indexes were calculated from time (RMSSD, pNN50, indexes of vagal tone) and frequency (LF, Low Frequency and HF, High Frequency as absolute values and in normalized units (nu); LF/HF ratio, index of sympathovagal balance) domains. The anaerobic threshold was evaluated by an incremental swimming test with lactate measurements. RESULTS. The percentage of swimmers who showed resting bradycardia tended to be higher in L (78%) than in S (54%) group. HRV indexes did not significantly differ between groups: RMSSD 67±23 vs 66±11 ms, pNN50 40±17 vs 48±10%, LFnu 62.3±12.3 vs 54.4±14.8, HFnu 37.6±12.3 vs 45.6±14.8, LF/HF 2.1±1.9 vs 1.5±1.0 (S vs L group, respectively). In S group, 50 m best time correlated positively (p<0.05) with RMSSD (r=0.64), pNN50 (r=0.73) and absolute HF power (r=0.64), and negatively with LFnu (r=-0.56), but not with anaerobic threshold. On the contrary, in L group 1500 m did not correlate with RMSSD, pNN50 and absolute HF power (although negative trends were perceived), negatively correlated with absolute LF power (r=-0.65 p=0.05), positively correlated to LFnu (r=0.72, p=0.02), and tended to increase with anaerobic threshold. CONCLUSION. L swimmers were not more hypervagotonic than S swimmers, and such adaptation tended to be positively associated with anaerobic threshold. Conversely, high vagal tone appeared somehow detrimental on short swimming performance, as it negatively predicts performance on 50 m events, whereas anaerobic threshold did not.
Settore BIO/09 - Fisiologia
Settore M-EDF/02 - Metodi e Didattiche delle Attivita' Sportive
American College of Sports Medicine
EFFECTS OF AUTONOMIC TONE ON SHORT VERSUS LONG DISTANCE PERFORMANCES IN SWIMMERS / M.A. Maggioni, A. Veicsteinas, C. Ciapparelli, P. Castiglioni, G. Merati. ((Intervento presentato al 59. convegno American College of Sports Medicine Annual Meeting 2012 tenutosi a San Francisco, CA nel 2012.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/2434/238700
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