Bioimpedance patterns and bioelectrical impedance vector analysis (BIVA) of road cyclists

Bioelectrical impedance vector-analysis (BIVA) describes cell-mass, cell function and hydration status of an individual or a group. The goal of the present investigation was to provide bioelectrical impedance data for 525 male road cyclists (155 professionals, 79 elite, 59 elite-youth, and 232 amateurs) at the time of their optimal performance level. Data were plotted on the resistance-reactance (R-Xc) graph to characterize cyclists group vectors using BIVA. Compared to the general male population, the mean vector position of the road cyclists indicates a higher body cell mass (BCM) and phase angle (p<0.001). The vector position of the high-performance, compared to the amateur cyclists showed similar patterns with higher BCM and phase angles and higher reactance values for the high-performance athletes (p<0.001). The bio-impedance data were used to calculate the 50%, 75%, and 95% tolerance ellipses of each group of cyclists. The characteristic vector positions of the road cyclists indicate normal hydration and greater muscle mass and function of the high-performance cyclists compared to amateur cyclists and the normal population. The cyclists specific tolerance ellipses, particularly the high-performance cyclists might be used for classifying a cyclist according to the individual vector position and to define target vector regions for lower level cyclists.     

Longitudinal monitoring of power output and heart rate profiles in elite cyclists

Abstract

Power output and heart rate were monitored for 11 months in one female ([Vdot]O_2max: 71.5 mL · kg^?1 · min^?1) and ten male ([Vdot]O_2max: 66.5 ± 7.1 mL · kg^?1 · min^?1) cyclists using SRM power-meters to quantify power output and heart rate distributions in an attempt to assess exercise intensity and to relate training variables to performance. In total, 1802 data sets were divided into workout categories according to training goals, and power output and heart rate intensity zones were calculated. The ratio of mean power output to respiratory compensation point power output was calculated as an intensity factor for each training session and for each interval during the training sessions. Variability of power output was calculated as a coefficient of variation. There was no difference in the distribution of power output and heart rate for the total season (P = 0.15). Significant differences were observed during high-intensity workouts (P < 0.001). Performance improvements across the season were related to low-cadence strength workouts (P < 0.05). The intensity factor for intervals was related to performance (P < 0.01). The variability in power output was inversely associated with performance (P < 0.01). Better performance by cyclists was characterized by lower variability in power output and higher exercise intensities during intervals.     

Differences in pedalling technique between road cyclists of different competitive levels

The purpose of this study was to compare the pedalling technique in road cyclists of different competitive levels. Eleven professional, thirteen elite and fourteen club cyclists were assessed at the beginning of their competition season. Cyclists’ anthropometric characteristics and bike measurements were recorded. Three sets of pedalling (200, 250 and 300 W) on a cycle ergometer that simulated their habitual cycling posture were performed at a constant cadence (~90 rpm), while kinetic and kinematic variables were registered. The results showed no differences on the main anthropometric variables and bike measurements. Professional cyclists obtained higher positive impulse proportion (1.5–3.3% and P < 0.05), mainly due to a lower resistive torque during the upstroke (15.4–28.7% and P < 0.05). They also showed a higher ankle range of movement (ROM, 1.1–4.0° and P < 0.05). Significant correlations (P < 0.05) were found between the cyclists’ body mass and the kinetic variables of pedalling: positive impulse proportion (r = ?0.59 to ?0.61), minimum (r = ?0.59 to ?0.63) and maximum torques (r = 0.35–0.47). In conclusion, professional cyclists had better pedalling technique than elite and club cyclists, because they opted for enhancing pulling force at the recovery phase to sustain the same power output. This technique depended on cycling experience and level of expertise.     

优秀中长距离自行车运动员4周高原训练 的机能监控

摘要：目的：旨在观察不同训练目的的4周高原训练对不同水平优秀自行车运动员身体机能的影响。方法：对8名优秀男子中长距离自行车运动员进行4周高原训练,内容包括公路专项力量、速度和公路有氧耐力,健将级组（c1）组以专项训练为主,一级组（C2）组以有氧耐力训练为主。每天监测晨脉;分别在高原训练2、3、4周和下高原1周后测试血常规;分别在大负荷训练后、休息后和下高原后2周测试血尿素（BU）、肌酸激酶（CK）;分别在高原训练前后测试身体成分。结果：两组晨脉均随运动负荷的变化而变化,并表现出高原训练早期升高后期下降的变化趋势;两组白细胞（WBC）和淋巴细胞（LY）均在高原训练期间有所降低,结束1周后回升,C1组变化幅度更大;两组血红蛋白（Hb）和红细胞压积（Hct）均在4周高原训练期间持续升高,并维持到结束后1周;C1组BU和CK变化与训练负荷相一致;高原训练后,C1组脂肪和C2组骨骼肌质量分别降低4．5％和3.9%.结论：自行车运动员身体机能对高原训练的适应性变化会受到高原训练经历和运动训练水平的影响。     

Effects of endurance training on transient oxygen uptake responses in cyclists

The aim of this study was to determine the alterations in oxygen uptake kinetics following endurance training in previously trained athletes. Sixteen competitive cyclists completed 8 weeks of supervised endurance cycle training. Ventilatory threshold, maximal oxygen uptake (VO2max), oxygen uptake kinetics and simulated 40-km time-trial tests were performed three times over a 4-week period before training, and then after 4 and 8 weeks of training. The protocol for measuring oxygen uptake kinetics consisted of three square-wave increments from unloaded cycling to a power output of 78 W followed by a single increment from 78 to 156 W. No significant differences in any variables were observed over the pre-training period. The ventilatory threshold and VO2max increased, and the time for 40 km decreased (P < 0.05) with training. Shorter VO2 time constants and lower heart rates were observed during the protocol for measuring oxygen uptake kinetics (same absolute power output) post-training. These results indicate that oxygen uptake kinetics may be improved with endurance training in previously trained athletes.     

Effects of inspiratory muscle training on time-trial performance in trained cyclists

We evaluated the effects of specific inspiratory muscle training on simulated time-trial performance in trained cyclists. Using a double-blind, placebo-controlled design, 16 male cyclists (VO 2max = 64 - 2 ml·kg -1 ·min -1 ; mean - sx ¥ ) were assigned at random to either an experimental (pressure-threshold inspiratory muscle training) or sham-training control (placebo) group. Pulmonary function, maximum dynamic inspiratory muscle function and the physiological and perceptual responses to maximal incremental cycling were assessed. Simulated time-trial performance (20 and 40 km) was quantified as the time to complete pre-set amounts of work. Pulmonary function was unchanged after the intervention, but dynamic inspiratory muscle function improved in the inspiratory muscle training group ( P h 0.05). After the intervention, the inspiratory muscle training group experienced a reduction in the perception of respiratory and peripheral effort (Borg CR10: 16 - 4% and 18 - 4% respectively; compared with placebo, P h 0.01) and completed the simulated 20 and 40 km time-trials faster than the placebo group [66 - 30 and 115 - 38 s (3.8 - 1.7% and 4.6 - 1.9%) faster respectively; P = 0.025 and 0.009]. These results support evidence that specific inspiratory muscle training attenuates the perceptual response to maximal incremental exercise. Furthermore, they provide evidence of performance enhancements in competitive cyclists after inspiratory muscle training.     

Effects of inspiratory muscle training on time-trial performance in trained cyclists

We evaluated the effects of specific inspiratory muscle training on simulated time-trial performance in trained cyclists. Using a double-blind, placebo-controlled design, 16 male cyclists (VO2max = 64 +/- 2 ml x kg(-1) x min(-1); mean +/- s(x)) were assigned at random to either an experimental (pressure-threshold inspiratory muscle training) or sham-training control (placebo) group. Pulmonary function, maximum dynamic inspiratory muscle function and the physiological and perceptual responses to maximal incremental cycling were assessed. Simulated time-trial performance (20 and 40 km) was quantified as the time to complete pre-set amounts of work. Pulmonary function was unchanged after the intervention, but dynamic inspiratory muscle function improved in the inspiratory muscle training group (P < or = 0.05). After the intervention, the inspiratory muscle training group experienced a reduction in the perception of respiratory and peripheral effort (Borg CR10: 16 +/- 4% and 18 +/- 4% respectively; compared with placebo, P < or = 0.01) and completed the simulated 20 and 40 km time-trials faster than the placebo group [66 +/- 30 and 115 +/- 38 s (3.8 +/- 1.7% and 4.6 +/- 1.9%) faster respectively; P = 0.025 and 0.009]. These results support evidence that specific inspiratory muscle training attenuates the perceptual response to maximal incremental exercise. Furthermore, they provide evidence of performance enhancements in competitive cyclists after inspiratory muscle training.     

Effects of strength training on physical fitness and sport-specific performance in recreational,sub-elite,and elite rowers: A systematic review with meta-analysis

ABSTRACT

The purpose of this systematic review with meta-analysis was to examine the effects of strength training (ST) on selected components of physical fitness (e.g., lower/upper limb maximal strength, muscular endurance, jump performance, cardiorespiratory endurance) and sport-specific performance in rowers. Only studies with an active control group were included if they examined the effects of ST on at least one proxy of physical fitness and/or sport-specific performance in rowers. Weighted and averaged standardized mean differences (SMD) were calculated using random-effects models. Subgroup analyses were computed to identify effects of ST type or expertise level on sport-specific performance. Our analyses revealed significant small effects of ST on lower limb maximal strength (SMD = 0.42, p = 0.05) and on sport-specific performance (SMD = 0.32, p = 0.05). Non-significant effects were found for upper limb maximal strength, upper/lower limb muscular endurance, jump performance, and cardiorespiratory endurance. Subgroup analyses for ST type and expertise level showed non-significant differences between the respective subgroups of rowers (p ≥ 0.32). Our systematic review with meta-analysis indicated that ST is an effective means for improving lower limb maximal strength and sport-specific performance in rowers. However, ST-induced effects are neither modulated by ST type nor rowers’ expertise level.     

10 weeks of heavy strength training improves performance-related measurements in elite cyclists

ABSTRACT

Elite cyclists have often a limited period of time available during their short preparation phase to focus on development of maximal strength; therefore, the purpose of the present study was to investigate the effect of 10-week heavy strength training on lean lower-body mass, leg strength, determinants of cycling performance and cycling performance in elite cyclists. Twelve cyclists performed heavy strength training and normal endurance training (E&S) while 8 other cyclists performed normal endurance training only (E). Following the intervention period E&S had a larger increase in maximal isometric half squat, mean power output during a 30-s Wingate sprint (P < 0.05) and a tendency towards larger improvement in power output at 4 mmol ? L^?1 [la^?] than E (P = 0.068). There were no significant difference between E&S and E in changes in 40-min all-out trial (4 ± 6% vs. ?1 ± 6%, respectively, P = 0.13). These beneficial effects may encourage elite cyclists to perform heavy strength training and the short period of only 10 weeks should make it executable even in the compressed training and competition schedule of elite cyclists.     

Body composition of female road and track endurance cyclists: Normative values and typical changes

The aims of this study were to describe normative values and seasonal variation of body composition in female cyclists comparing female road and track endurance cyclists, and to validate the use of anthropometry to monitor lean mass changes. Anthropometric profiles (seven site skinfolds) were measured over 16 years from 126 female cyclists. Lean mass index (LMI) was calculated as body weight?×?skinfolds^?x. The exponent (x) was calculated as the slope of the natural logarithm of body weight and skinfolds. Percentage changes in LMI were compared to lean mass changes measured using dual-energy X-ray absorptiometry (DXA) in a subset of 25 road cyclists. Compared to sub-elite and elite cyclists, world class cyclists were (mean [95% CI]) 1.18?kg [0.46, 1.90] and 0.60?kg [0.05, 1.15] lighter and had skinfolds that were 7.4?mm [3.8, 11.0] and 4.6?mm [1.8, 7.4] lower, respectively. Body weight (0.41?kg [0.04, 0.77]) and skinfolds (4.0?mm [2.1, 6.0]) were higher in the off-season compared to the early-season. World class female road cyclists had lower body weight (6.04?kg [2.73, 9.35]) and skinfolds (11.5?mm [1.1, 21.9]) than track endurance cyclists. LMI (mean exponent 0.15 [0.13, 0.18]) explained 87% of the variance in DXA lean mass. In conclusion, higher performing female cyclists were lighter and leaner than their less successful peers, road cyclists were lighter and leaner than track endurance cyclists, and weight and skinfolds were lowest early in the season. LMI appears to be a reasonably valid tool for monitoring lean mass changes.     

世居高原自行车运动员亚高原训练期间身体机能变化

目的:观察世居高原自行车运动员在亚高原训练期间的机能变化.方法:以8名世居高原(海拔1910m)男子公路自行车运动员为研究对象,系统测试每名运动员在下亚高原前、亚高原(海拔1300m)训练第2天、第4天、第8天、第18天、第25天及第32天的红细胞(RBC)、红细胞压积(Hct)、血红蛋白(Hb)、血清睾酮(T)、皮质醇(C)、晨脉(HR)、脉搏血氧饱和度(SpO2)等血液生化指标及生理指标.结果:①世居高原运动员下到亚高原环境,大气氧分压增加了10mmHg,运动员Sp02上升了1％,晨脉下降了5次/分,均无统计学差异.②运动员RBC、Hct、Hb在亚高原训练的第2天开始下降,并在第4天降至最低,RBC下降明显(P＜0.01),较高原下降了9.25％,Hb稍有下降;一周后各血象指标逐渐回升,并在第25天时升至最高水平,Hb升高了4.33％,且差异显著(P＜0.05),RBC无变化.③运动员血清T在亚高原训练的前3周与高原相比无差异,3周后升高,并在第25天显著升高(P＜0.05),较高原升高15.56％;C在第二天较高,随后下降,T/C比值变化甚微.结论:世居高原男子自行车运动员亚高原训练期间第1周身体机能状况较差,随后逐渐恢复,在3周后达到最好水平.提示世居高原男子自行车运动员到亚高原比赛时的最佳时间为下至亚高原3周后.     

运动中补充西番莲、奥华运动饮料的效果研究

对运动员服用西番莲、奥华两种饮料前后的运动能力及生理生化指标分析测定,发现这两种饮料能使运动员运动至疲劳的时间明显延长,维持血容量,使运动中血糖水平保持正常,并使血清镁离子浓度维持正常水平。     

The effect of a complex training and detraining programme on selected strength and power variables in early pubertal boys

Abstract

Complex training, a combination of resistance training and plyometrics is growing in popularity, despite limited support for its efficacy. In pre- and early pubertal children, the study of complex training has been limited, and to our knowledge an examination of its effect on anaerobic performance characteristics of the upper and lower body has not been undertaken. Furthermore, the effect of detraining after complex training requires clarification. The physical characteristics (mean±s) of the 54 male participants in the present study were as follows: age 12.3 ± 0.3 years, height 1.57 ± 0.07 m, body mass 50.3 ± 11.0 kg. Participants were randomly assigned to an experimental (n = 33) or control group (n = 21). The training, which was performed three times a week for 12 weeks, included a combination of dynamic constant external resistance and plyometrics. After training, participants completed 12 weeks of detraining. At baseline, after training and after detraining, peak and mean anaerobic power, dynamic strength and athletic performance were assessed. Twenty-six participants completed the training and none reported any training-related injury. Complex training was associated with small increases (≤5.5%) in peak and mean power during training, followed by decreases of a similar magnitude (≤ ?5.9%) during detraining (P < 0.05). No changes or minor, progressive increases (≤1.5%) were evident in the control group (P > 0.05). In the experimental group, dynamic strength was increased by 24.3 – 71.4% (dependent on muscle group; P < 0.01), whereas growth-related changes in the control group varied from 0 to 4.4% (P > 0.05). For 40-m sprint running, basketball chest pass and vertical jump test performance, the experimental group saw a small improvement (≤4.0%) after training followed by a decline (≤ ?4.4%) towards baseline during detraining (P < 0.05), whereas the control group experienced no change (P > 0.05). In conclusion, in pre- and early pubertal boys, upper and lower body complex training is a time-effective and safe training modality that confers small improvements in anaerobic power and jumping, throwing and sprinting performance, and marked improvements in dynamic strength. However, after detraining, the benefits of complex training are lost at similar rates to other training modalities.     

Predictive value of coaches’ early technical and tactical notational analyses on long-term success of female handball players

ABSTRACT

Despite the importance of technique and tactics for athlete performance, there has been surprisingly little research on the value of these skills in talent identification and development. This study investigated the relationship between coaches’ early notational analyses of female youth handball players and the long-term success of these athletes. Participants included sixty-eight female handball players involved in a talent selection camp in Germany when they were between 12 and 14 years of age (mean = 14.42, SD = 0.42). All subsequently ended up as non-, semi- or professional adult players. During the initial selection camp, participants were evaluated on a range of quantitative and qualitative measures of technical and tactical skill. Results indicated significant differences between the groups, but only for the number of actions taken, not for the quality of those actions. While this seems counterintuitive, it may reflect the likelihood that more skilled and/or talented players take more actions. Further work is necessary to explore the validity and implications of these findings.     

运动锻炼影响体脂代谢的研究进展

体育锻炼是减少体脂含量和提高运动性能的一种有效方法。本文就运动锻炼影响体脂代谢的研究进展作一综述。     

Neuromuscular adaptations to sixteen weeks of whole-body high-intensity interval training compared to ergometer-based interval and continuous training

The neuromuscular adaptations between ergometer-based high-intensity interval training (HIIT-T; n = 15), whole-body high-intensity interval training (HIIT-WB; n = 12) and moderate-intensity continuous training (MICT; n = 14) were compared in forty-one healthy men randomized to 16 weeks of training (3x per week). Two-way repeated measures analysis of variance (ANOVA) showed countermovement (CMJ) and squat (SJ) jump height (HIIT-T: 8.5 ± 13.3%; 3.1 ± 9.7%, HIIT-WB: 6.4 ± 9.8%, 10.4 ± 16.1% and MICT: 2.2 ± 9.5%; 4.4 ± 12.1%, respectively), SJ peak power (HIIT-T: 1.7 ± 3.9%; HIIT-WB : 6.4 ± 7.9%; MICT: 0.5 ± 6.5%) and CMJ rate of force development (HIIT-T: 58.1 ± 50.5%; HIIT-WB: 36.9 ± 54.2%; MICT: 38.4 ± 64.3%) improved similarly in all training groups (all p < 0.05). CMJ peak power increased only after HIIT-T (4.3 ± 5.5%) and HIIT-WB (4.5 ± 5.2%), while no differences were observed in both the rectus femoris and vastus lateralis maximal electromyographic amplitude. Finally, marked improvements were also observed in the number of repetitions in the HIIT-WB protocol at the eighth week, with no further improvement at the sixteenth week. These data suggest that 16 weeks of HIIT-WB is capable to improve neuromuscular function to a similar extent as HIIT-T and MICT.     

运动训练视角下力量分类的研究

通过文献资料法、专家访谈法并结合运动训练实践,从运动训练的视角对当前力量的分类及构成进行了分析与探索,将运动训练划分为基础训练、功能性训练和专项训练,并据此将力量划分为基础力量、功能性力量和专项力量,同时通过对三者之间内在关系的剖析,对当前力量分类研究进行了尝试性探索。     

我国运动训练领域诸多理念的辨析及其发展新动向

训练理念对运动训练的效果起着深刻的作用。竞技运动训练一直在随着比赛数量的增加而在不断地改变,优秀运动员欲想在多次比赛中获胜,就必须改变训练的方式和方法,使训练适应并满足比赛的需求。不能完整、准确和有针对性地解释、定位专项运动特征是我国竞技运动训练中长期存在的问题。对专项运动内在、微观和动态的细节变化进行深入了解和认识是当前探索和研究专项特征的主要发展趋势。“乳酸阚模式”和“两极化模式”建立在不同的研究对象基础之上,它们在训练实践中的适用范围不同。以生物学理论为基础的中国运动训练理念的创新,主要通过适合的负荷强度刺激以及训练量的延伸,使运动员身体器官对训练负荷产生竞赛强度的适应性,从而有效提高运动员竞技水平。     

Cardiorespiratory and perceptual responses of two interval training and a continuous training protocol in healthy young men

High Intensity Interval Training (HIIT) can be performed with different effort to rest time-configurations, and this can largely influence training responses. The purpose of the study was to compare the acute physiological responses of two HIIT and one moderate intensity continuous training (MICT) protocol in young men. A randomised cross-over study with 10 men [age, 28.3?±?5.5years; weight, 77.3?±?9.3?kg; height, 1.8?±?0.1?m; peak oxygen consumption (VO₂peak), 44?±?11?mL.kg^?1.min^?1]. Participants performed a cardiorespiratory test on a treadmill to assess VO₂peak, velocity associated with VO₂peak (vVO₂peak), peak heart rate (HRpeak) and perceived exertion (RPE). Then participants performed three protocols equated by distance: Short HIIT (29 bouts of 30s at vVO₂peak, interspersed by 30s of passive recovery, 29?min in total), Long HIIT (3 bouts of 4?min at 90% of vVO₂peak, interspersed by 3?min of recovery at 60% of vVO₂peak, 21?min in total) and MICT (21?min at 70% of vVO₂peak). The protocols were performed in a randomised order with ≥48 h between them. VO₂, HRpeak and RPE were compared. VO₂peak in Long HIIT was significantly higher than Short HIIT and MICT (43?±?11 vs 32?±?8 and 37?±?8?mL.kg^?1.min^?1, respectively, P?P?P?2, HR and RPE than Short HIIT and MICT, suggesting a higher demand on the cardiorespiratory system. Short HIIT and MICT presented similar physiologic and perceptual responses, despite Short HIIT being performed at higher velocities.     

Influence of force-vector and force application plyometric training in young elite basketball players

Plyometric training composed by unilateral exercises with horizontal jumping direction seems to be an effective way to improve physical performance in athletes. The present study aimed to compare the influence of a combined jumping direction and force application (horizontal-unilateral vs. vertical-bilateral) plyometric training on linear sprinting, jumping, change of direction (COD) and dynamic balance in young elite basketball players. Twenty young (U-13 to U-14) male basketball players (age: 13.2?±?0.7 years, body mass: 59.5?±?12.7?kg, height: 172.9?±?7.9?cm) were randomly assigned either to a unilateral-horizontal (UH, n?=?10) or bilateral-vertical (BV, n?=?10) plyometric group, twice a week for 6-wk. Both groups performed between 60 and 100 jumps/session. UH executed all jumps unilaterally with horizontal direction, while jumps in the BV were bilaterally with vertical direction. Performance was assessed by a linear sprinting test, vertical and horizontal jumping tests, COD tests (V-cut and 5+5?m with a 180°COD test), an ankle dorsiflexion test and dynamic balance tests (anterior and postero-lateral directions). Within-group differences showed substantial improvements (Effect size (ES):0.31–1.01) in unilateral vertical and horizontal jumping, V-cut test and postero-lateral direction with right leg after both training interventions. Furthermore, UH group also substantially improved (ES:0.33–0.78) all sprinting times and postero-lateral direction with left leg, while BV enhanced anterior direction with left leg (ES:0.25). Between-group analyses showed substantially greater improvements (ES:0.33) in 10-m and V-cut test in UH than in BV. The likely beneficial effect (small ES) achieved in sprinting abilities suggests the combination of unilateral-horizontal jumps to improve such abilities.