Physiological Effects of Tapering and Detraining in World-Class Kayakers

. Purpose: This study analyzed changes in neuromuscular, body composition, and endurance markers during 4 wk of tapering and subsequent 5 wk of reduced training (RT) or training cessation (TC). Methods: Fourteen world-class kayakers were randomly assigned to either a TC (n = 7) or an RT group (n = 7). One-repetition maximum (1RM) strength, mean concentric velocity with 45% 1RM (V 45% ) in the bench press (BP) and prone bench pull (PBP) exercises, and body composition assessments were conducted at the start (T0) and end (T1) of a 43-wk training program, after tapering for the world championships (T2) and after TC or RT (T3). A graded exercise test on a kayak ergometer for determination of maximal oxygen uptake at T0, T1, and T3 was also performed. Results: After tapering, no significant changes were observed in 1RM or V 45% . TC resulted in significantly greater declines in 1RM strength (j8.9% and j7.8%, P G 0.05, respectively, for BP and PBP) than those observed for RT (j3.9% and j3.4%). Decreases in V 45% in BP and PBP were larger for TC (j12.6% and j10.0%) than for RT (j9.0% and j6.7%). Increases in sum of eight skinfolds were observed after both TC and RT, whereas declines in maximal aerobic power were lower for RT (j5.6%) than for TC (j11.3%). Conclusions: Short-term TC results in large decreases in maximal strength and especially V 45% in highly trained athletes. These results suggest the need of performing a minimal maintenance program to avoid excessive declines in neuromuscular function in cases where a prolonged break from training is required. Key Words: TRAINING CESSATION, REDUCED TRAINING, MAXIMAL STRENGTH, MUSCLE POWER, CANOEING A well-known and proven effective coaching strategy for improving sports performance before main competition events is to incorporate a tapering phase of significantly reduced training (RT) volume while the intensity is kept high The incorporation of periods of 3-6 wk of training cessation (TC) after the conclusion of the main event of the season to allow physical and mental recovery before the start of a new training cycle is a common training practice in many sports. In these situations, training reduction is generally preferred over complete exercise stoppage because it seems to be more effective to avoid the negative impact of insufficient training stimuli on athletic performance (21). The magnitude of performance declines observed after detraining periods appears to be related to the chosen recovery strategy (i.e., reduced training (RT) or complete training cessation (TC)), initial fitness level, and total time under reduced or absence of training stimuli Current research seems to indicate that neuromuscular performance is more susceptible to decline because of detraining in highly trained athletes compared with recently or moderately trained individual

Improvements cardiometabolic risk factors in Latin American Amerindians (the Mapuche) with concurrent training

Our aim was to investigate the effects of 12 weeks of CT (ie, high‐intensity interval and resistance training) in Mapuche adults from Chile and in their peers of European descent. In total, 96 hyperglycemic adult women (mean age 46 years [95% confidence interval; 38, 53]) were divided in four groups: Mapuche CT (Map‐CT, n = 14) or control group (Map‐CG, n = 44), and European CT (Eur‐CT, n = 14) or control group (Eur‐CG, n = 23). The following endpoints were analyzed at baseline and after 12 weeks: anthropometric (body mass, body mass index, waist circumference), body composition (fat mass, muscle mass, lean mass), cardiovascular (systolic [SBP]/diastolic [DBP] blood pressure), metabolic (blood fasting glucose and total cholesterol), and muscle strength (handgrip of dominant/non‐dominant arm). There were significant positive changes in body mass, body fat, and muscle mass (P < 0.0001) in both Map‐CT and Eur‐CT groups, whereas waist circumference was decreased significantly only in the Eur‐CT group (P < 0.0001). Both Map‐CT and Eur‐CT groups showed decreased levels of fasting glucose (P < 0.05) and total cholesterol after the intervention (P < 0.0001). Also, both Map‐CT (P < 0.05) and Eur‐CT (P = 0.01) groups showed a lowered SBP. Finally, significant increases were observed after training in handgrip strength (dominant arm) in Map‐CT and Eur‐CT groups (both P < 0.0001). CT led to similar improvements in cardiometabolic risk factors for metabolic syndrome development in Mapuche and European participants, with additional improvements in other anthropometric, body composition, cardiovascular, metabolic, and muscle strength parameters related to the prevention of metabolic syndrome. These results suggest future more complex studies.Concurso Buenas Practicas en Promoción de La Salud, Región de Los RíosISCIII and Fondos FEDER (PI17/01814 and PI15/00558)Comite de Becas de internacionalización de la Universidad del Rosario (Contract No 10004611 de 2017)3.255 JCR (2019) Q1, 14/85 Sport Sciences1.373 SJR (2019) Q1, 28/284 Orthopedics and Sports Medicine, 10/207 Physical Therapy, Sports Therapy and Rehabilitation, 19/125 Sports ScienceNo data IDR 2019UE

Low sleep time is associated with higher levels of blood pressure and fat mass in Amerindian schoolchildren

Objectives While altered sleep patterns (ie, low sleep time) have been studied and reported in adults as a new cardiometabolic risk factor, less information is available on how sleep patterns impact children of different ethnicities. The aim of this study was to compare the levels of blood pressure and other cardiometabolic risk factors in relation to different levels of sleep time in schoolchildren of Amerindian Mapuche or European‐ancestry of Southern Chile. Methods In a cross‐sectional study, 540 Chilean schoolchildren (6‐13 years) were divided into two ethnic groups (n = 119 Mapuche Amerindians and n = 421 European‐ancestry). Groups were analyzed according to sleep time per day as registered by parents' report and distributed into quartile categories of sleep time: Mapuche (quartile 1 [Q1] ≥10.0 h, n = 34; Q2 9.5‐10.0 h, n = 29; Q3 8.5‐9.0 h, n = 31; and Q4 ≤ 8.5 h, n = 25), and European (Q1, n = 99; Q2, n = 77; Q3, n = 144; Q4, n = 101). The main cardiovascular parameters (systolic [SBP] and diastolic blood pressure) were complemented with anthropometric/body composition (body mass, body mass index [BMI], waist circumference, fat mass, muscle mass, lean mass), cardiorespiratory (heart rate rest, oxygen saturation), and muscle strength (handgrip of dominant and non‐dominant arm) outcomes. Results From Q1 and across Q2, Q3, and Q4, there was an increase in delta mean SBP in both Mapuche (Δ +17.6 mm Hg) and European (Δ +7.3 mm Hg) schoolchildren with 30‐90 min of decreased sleep time (using ≥10 h as reference in Q1). The tendency for worsening of other cardiometabolic risk factors was maintained for delta mean BMI (Δ +2.6 kg/m2), waist circumference (Δ +12 cm), and fat mass (Δ +8.3%) in Mapuches, whereas European peers showed only worsened waist circumference (Δ +6 cm) across Q2, Q3, and Q4 in comparison with reference Q1. There was also a higher prevalence of hypertension in Mapuche (31.1%) compared to in European schoolchildren (17.6%). Conclusions Mapuche and European schoolchildren show higher levels of SBP with a decrease in sleep time of 30 min; however, there is a higher prevalence of hypertension and obesity in ethnic Mapuches than in European schoolchildren. These findings indicate that more studies should be applied at early school ages for preventing low sleep time and their related cardiometabolic risk factors for hypertension development in different ethnic groups.Sin financiación1.558 JCR (2019) Q2, 28/90 Anthropology; Q3, 61/93 Biology0.565 SJR (2019) Q1, 64/427 Anthropology; Q2, 15/42 Anatomy, 273/663 Ecology, Evolution, Behavior and Systematics; Q3, 236/346 GeneticsNo data IDR 2019UE

Gross efficiency predicts a 6-min double-poling ergometer performance in recreational cross-country skiers

The purpose of the study was to investigate which physiological parameters would most accurately predict a 6-min, all-out, double-poling (DP) performance in recreational cross-country skiers. Twelve male recreational cross-country skiers performed tests consisting of three series lasting 10 s, one lasting 60 s, plus a 6-min, all-out, DP performance test to estimate mean and peak power output. On a separate day, gross mechanical efficiency (GE) was estimated from a 10-min, submaximal, DP test and maximal oxygen consumption (VO2 max) was estimated from an incremental treadmill running test. Power was measured after each stroke from the acceleration and deceleration of the flywheel that induced the friction on the ergometer. The power was shown to the skier on a small computer placed on the ergometer. A multivariable correlation analysis showed that GE most strongly predicted 6-min DP performance (r = 0.79) and interestingly, neither DP VO2 max, nor treadmill-running VO2 max, correlated with 6-min DP performance. In conclusion, GE correlated most strongly with 6-min DP performance and GE at the ski ergometer was estimated to be 6.4 ± 1.1%. It is suggested that recreational cross-country skiers focus on skiing technique to improve gross mechanical efficiency during intense DP