Large asymmetric hypertrophy of rectus abdominis muscle in professional tennis players

Purpose

To determine the volume and degree of asymmetry of the musculus rectus abdominis (RA) in professional tennis players.

Methods

The volume of the RA was determined using magnetic resonance imaging (MRI) in 8 professional male tennis players and 6 non-active male control subjects.

Results

Tennis players had 58% greater RA volume than controls (P = 0.01), due to hypertrophy of both the dominant (34% greater volume, P = 0.02) and non-dominant (82% greater volume, P = 0.01) sides, after accounting for age, the length of the RA muscle and body mass index (BMI) as covariates. In tennis players, there was a marked asymmetry in the development of the RA, which volume was 35% greater in the non-dominant compared to the dominant side (P<0.001). In contrast, no side-to-side difference in RA volume was observed in the controls (P = 0.75). The degree of side-to-side asymmetry increased linearly from the first lumbar disc to the pubic symphysis (r = 0.97, P<0.001).

Conclusions

Professional tennis is associated with marked hypertrophy of the musculus rectus abdominis, which achieves a volume that is 58% greater than in non-active controls. Rectus abdominis hypertrophy is more marked in the non-dominant than in the dominant side, particularly in the more distal regions. Our study supports the concept that humans can differentially recruit both rectus abdominis but also the upper and lower regions of each muscle. It remains to be determined if this disequilibrium raises the risk of injury.     

Iliopsoas and gluteal muscles are asymmetric in tennis players but not in soccer players

Purpose

To determine the volume and degree of asymmetry of iliopsoas (IL) and gluteal muscles (GL) in tennis and soccer players.

Methods

IL and GL volumes were determined using magnetic resonance imaging (MRI) in male professional tennis (TP) and soccer players (SP), and in non-active control subjects (CG) (n = 8, 15 and 6, respectively).

Results

The dominant and non-dominant IL were hypertrophied in TP (24 and 36%, respectively, P<0.05) and SP (32 and 35%, respectively, P<0.05). In TP the asymmetric hypertrophy of IL (13% greater volume in the non-dominant than in the dominant IL, P<0.01) reversed the side-to-side relationship observed in CG (4% greater volume in the dominant than in the contralateral IL, P<0.01), whilst soccer players had similar volumes in both sides (P = 0.87). The degree of side-to-side asymmetry decreased linearly from the first lumbar disc to the pubic symphysis in TP (r = −0.97, P<0.001), SP (r = −0.85, P<0.01) and CG (r = −0.76, P<0.05). The slope of the relationship was lower in SP due to a greater hypertrophy of the proximal segments of the dominant IL. Soccer and CG had similar GL volumes in both sides (P = 0.11 and P = 0.19, for the dominant and contralateral GL, respectively). GL was asymmetrically hypertrophied in TP. The non-dominant GL volume was 20% greater in TP than in CG (P<0.05), whilst TP and CG had similar dominant GL volumes (P = 0.14).

Conclusions

Tennis elicits an asymmetric hypertrophy of IL and reverses the normal dominant-to-non-dominant balance observed in non-active controls, while soccer is associated to a symmetric hypertrophy of IL. Gluteal muscles are asymmetrically hypertrophied in TP, while SP display a similar size to that observed in controls. It remains to be determined whether the different patterns of IL and GL hypertrophy may influence the risk of injury.     

Muscle hypertrophy in bodybuilders

Muscle biopsy samples were obtained from m. vastus lateralis and m. deltoideus of three high caliber bodybuilders. Tissue specimens were analysed with respect to relative distribution of fast twitch (FT) and slow twitch (ST) fiber types and different indices of fiber area. In comparison to a reference group of competitive power/weight-lifters the following tendencies were observed: the percentage of FT fibers was less, mean fiber area was smaller and selective FT fiber hypertrophy was not evident. Values for fiber type composition and fiber size were more similar to values reported for physical education students and non-strength trained individuals. The results suggest that weight training induced muscle hypertrophy may be regulated by different mechanisms depending upon the volume and intensity of exercise.     

Physiological responses of skilled players during a competitive wheelchair tennis match

The purpose of this study was to determine heart rate (HR, b.min(-1)) response during competitive match play of 6 men who were skilled wheelchair (WC) tennis players. Each participant completed an arm crank ergometer test that measured HR via a telemetry device and O2 via open circuit spirometry from rest until fatigue (.V(O2)peak). Each athlete participated in 2 competitive singles matches during which HRs were recorded in 5-second intervals and O2 was estimated using the corresponding HR values recorded during the arm ergometer tests. Data analysis revealed an average playing intensity of 69.4 +/- 8.9% of HRpeak and 49.9 +/-14.5% of .V(O2)peak. In conclusion, it is recommended that skilled adult WC tennis players perform off-court aerobic conditioning as part of their training program, because the intensity of a competitive WC tennis match is sufficiently high enough to stress the cardiovascular system.     

Enhanced temporal but not attentional processing in expert tennis players

In tennis, as in many disciplines of sport, fine spatio-temporal resolution is required to reach optimal performance. While many studies on tennis have focused on anticipatory skills or decision making, fewer have investigated the underlying visual perception abilities. In this study, we used a battery of seven visual tests that allowed us to assess which kind of visual information processing is performed better by tennis players than other athletes (triathletes) and non-athletes. We found that certain time-related skills, such as speed discrimination, are superior in tennis players compared to non-athletes and triathletes. Such tasks might be used to improve tennis performance in the future.     

Comparison of two aerobic field tests in young tennis players

ABSTRACT: Fargeas-Gluck, M-A and Léger, LA. Comparison of two aerobic field tests in young tennis players. J Strength Cond Res 26(11): 3036-3042, 2012-This study compares the maximal responses of a new aerobic tennis field test, the NAVTEN to a known aerobic field test, often used with young tennis players, that is, the continuous multistage 20-m shuttle run test (20-m SRT). The NAVTEN is an intermittent (1-minute/1-minute) multistage test with side-to-side displacements and ball hitting. Ten young elite tennis players aged 12.9 ± 0.3 (mean ± SD) randomly performed both tests and were continuously monitored for heart rate (HR) and oxygen uptake (V[Combining Dot Above]O2) using the Vmax ST (Sensormedics). The 20-m SRT and NAVTEN show similar HRpeak (202 ± 6.1 vs. 208 ± 9.5, respectively) and V[Combining Dot Above]O2peak (54.2 ± 5.9 vs. 54.9 ± 6.0 ml·kg·min). Pearson correlations between both tests were 0.88 and 0.92 for V[Combining Dot Above]O2peak and maximal speed, respectively. The NAVTEN yielded V[Combining Dot Above]O2peak values that are typical for active subjects of that age and are similar to the 20-m SRT supporting its use to measure aerobic fitness of young tennis players in specific and entertaining field conditions. The fact that two-thirds of the tennis players achieved a different ranking (±1 rank) with the NAVTEN and the 20-m SRT suggests that the NAVTEN may be more specific than the 20-m SRT to assess aerobic fitness of tennis players. From a practical point of view, the NAVTEN test is more specific and pedagogical for young tennis players even though both tests yield similar maximal values.     

Enhanced maximal metabolic vasodilatation in the dominant forearms of tennis players

In an effort to evaluate potential peripheral adaptations to training, maximal metabolic vasodilation was studied in the dominant and nondominant forearms of six tennis players and six control subjects. Maximal metabolic vasodilation was defined as the peak forearm blood flow measured after release of arterial occlusion, the reactive hyperemic blood flow (RHBF). Two ischemic stimuli were employed in each subject: 5 min of arterial occlusion (RHBF5) and 5 min of arterial occlusion coupled with 1 min of ischemic exercise (RHBF5ex). RHBF and resting forearm blood flows were measured using venous occlusion strain-gauge plethysmography (ml X min-1 X 100 ml-1). Resting forearm blood flows were similar in both arms of both groups. RHBF5ex was similar in both arms of our control group (dominant, 40.8 +/- 1.2 vs. nondominant, 40.9 +/- 2.1). However, RHBF5ex was 42% higher in the dominant than in the nondominant forearms of our tennis player population (dominant, 48.7 +/- 4.0 vs. nondominant, 34.4 +/- 3.4; P less than 0.05). This intraindividual difference in peak forearm blood flows was not secondary to improved systemic conditioning since the maximal O2 consumptions in the two study groups were similar (controls, 45.4 +/- 3.9 vs. tennis players, 46.1 +/- 1.7). These findings suggest a primary peripheral cardiovascular adaptation to exercise training in the dominant forearms of the tennis players resulting in a greater maximal vasodilatation.     

Racial equality in France and the United States: media coverage of professional tennis players

I engage debates about racial media bias by analysing newspaper coverage of professional tennis players in France and the United States. Tennis is an elite sport that typically does not have many non-white players and may be especially sensitive to racial boundaries. Tennis also offers a new solution to the methodological challenge of establishing that any difference in newspaper coverage across racial groups is due to bias and not actual differences across the groups. I use the professional tennis ranking system, which assigns an objective marker of how good a player is (and therefore the media coverage that s/he should receive) at any point in time. I explore two types of bias (the amount and tone of media coverage) and uncover no systematic racial differences in the relationship between ranking and media coverage. My findings have several implications for our understanding of racial boundaries and the media.     

Effects of isoinertial or machine-based strength training on performance in tennis players

The objective of this study was to analyze the effects of two 8-week neuromuscular training (NMT) interventions on selected physical indicators in young tennis players. Twenty-four junior male tennis players were assigned to a machine-based (MG) (n = 8), flywheel (FG) (n = 8) or a control training group (CG) (n = 8). Tests at baseline, week 4 and 8 included: countermovement jump (CMJ); speed (S; 5, 10, 15 m); agility (right [AR] and left [AL]); serve velocity (SV) and medicine ball throws (MBT; overhead [O], forehand [FH], backhand [BH]). MG and FG attained large positive effects at week 4 in CMJ, S 10 m; AR, AL and MBT FH only in FG. Regarding inter- to post-test, MG achieved large positive effects in MBT O, FH and both groups in BH. Large negative effects appeared for FG in S 5 and 10 m and AR and AL. Both NMT interventions led to positive effects from baseline to week 4 measures in CMJ, S 5 m, 10 m and agility and at week 8 in MBT. Conducting the same NMT for a longer period of time did not lead to the same improvements and other negative effects in FG appeared. Results indicate that performing these interventions with little exercise variability or load management, especially after technical-tactical sessions, could interpose further beneficial outcomes and initial gains could be impaired.     

Muscle hypertrophy in rats fed on a buckwheat protein extract.

Growing rats were examined for the influence of a buckwheat protein diet on muscle weight and protein. In experiment 1, the rats were fed on a diet containing either casein or a buckwheat protein extract (BWPE) as the protein source (10%, 20% or 30%) for 5 wk. The relative weights (g per kg of body wt) of the gastrocnemius, plantaris and soleus muscles were higher in the BWPE-fed animals than in the casein-fed ones, but were unaffected by the dietary level of protein. These differences were not associated with growth. In experiment 2, the rats were fed on either a casein or BWPE diet at the 20% protein level for 5 wk. BWPE intake significantly elevated the gastrocnemius muscle weight, carcass protein and water, and reduced carcass fat. These results demonstrate that BWPE consumption causes muscle hypertrophy, elevates carcass protein and water, and reduces body fat.     

Winner and loser effects in human competitions. Evidence from equally matched tennis players

Animals winning an agonistic encounter are more likely to win their next encounter while losers are less likely, even when controlling for motivation and physical size. Do these winner and loser effects exist in human competitions? Drawing on a large database of professional tennis matches, we were able to control for players' ability and thereby test for winner and loser effects. We narrowed the database to matches between players who on average did not differ significantly in rank, and further to matches in which the first set was fought to a long tie-break. These closely fought matches present a natural experiment because players are assigned to treatment conditions – winning or losing a set – despite similar ability and performance. We found that among men, the winner of a closely fought tie-break had an approximate 60% chance of winning the second set, the loser a 40% chance. These effects did not exist among women, a finding consistent with the hypothesis that androgens mediate winner and loser effects. Our results may help in the design of competitions in sport as well as in work environments, where it may prove useful to either encourage winner effects or to attenuate their occasional adverse consequences.     

能量消耗C指标在评价乒乓球运动员多球练习中能量消耗的应用*

目的:研究周期类运动能量消耗^C指标在评价乒乓球多球练习中能量消耗应用的可行性。方法:11名某大学代表队的乒乓球运动员(18±1 yrs, 177±2 cm, 71±3 kg,运动水平≥二级)自愿参加了1次跑台递增负荷测试和2次(正手和反手)发球机多球递增频率测试(3 min × 6级,频率为35~85 stroke·min^-1)。用便携式气体代谢仪和心率监测仪检测3次测试的呼吸气体和心率,计算每种频率下每次击球所消耗的能量;采集运动前后的耳血进行血乳酸分析。结果:乒乓球前冲弧圈多球练习的能量消耗^C随击球频率的增加而下降(P＜0.05)。6种击球频率下,正手前冲弧圈的能量消耗^C都高于反手,且差异在35、45、55、65和85 stroke·min^-1时显著(P＜0.05)。能量消耗^C与频率的关系公式分别为y=166.4x^-0.731(R²=0.9731)和y=33.21x^-0.392(R²=0.8423),其中y为能量消耗^C(单位为J·stroke^-1·kg^-1),x为击球频率(单位为stroke·min^-1)。结论:周期类运动项目的能量消耗^C可应用于评价乒乓球运动员单一技术动作多球练习的能量消耗,反映乒乓球运动员在不同击球频率下的击球效率。