Biological characteristics of young swimmers, tennis players and non-competitors

A 2-year longitudinal follow-up of performance characteristics in Chinese male elite youth athletes from swimming and racket sports

Training in elite sport aims at the optimization of the athletic performance, and to control the athletes`progress in physiological, anthropometrical and motor performance prerequisites. However, in most sports, the value of longitudinal testing is unclear. This study evaluates the longitudinal development and the influence of intense training over 2-years on specific physiological performance prerequisites, as well as certain body dimensions and motor abilities in elite youth athletes. Recruited between 11-13 years of age at Shanghai Elite Sport school, the sample of student-athletes (N = 21) was categorized as the swimming group (10 athletes), and the racket sports group (11 players: 7 table tennis and 4 badminton players). The performance monitoring took place over two years between September 2016 and September 2018 and included 5 test waves. In all the test waves, the athletes were assessed by means of three physiological measurements (vital capacity, hemoglobin concentration, heart rate at rest), three anthropometric parameters (body height, body weight, chest girth), and two motor tests (back strength, complex reaction speed). Seven out of eight diagnostic methods exhibit medium to high validity to discriminate between the different levels of performance development in the two sports groups. The investigated development of the performance characteristics is attributed partly to the inherited athletic disposition as well as to the different sport-specific training regimens of the two sports groups.

Prediction of Tennis Performance in Junior Elite Tennis Players

Predicting current and future tennis performance can lead to improving the development of junior tennis players. The aim of this study is to investigate whether age, maturation, or physical fitness in junior elite tennis players in U13 can explain current and future tennis performance. The value of current tennis performance for future tennis performance is also investigated. A total of 86 junior elite tennis players (boys, n = 44; girls, n = 42) U13 (aged: 12.5 ± 0.3 years), and followed to U16, took part in this study. All players were top-30 ranked on the Dutch national ranking list at U13, and top-50 at U16. Age, maturation, and physical fitness, were measured at U13. A principal component analysis was used to extract four physical components from eight tests (medicine ball throwing overhead and reverse, ball throwing, SJ, CMJas, Sprint 5 and 10 meter, and the spider test). The possible relationship of age, maturation, and the physical components; "upper body power", "lower body power", "speed", and "agility" with tennis performance at U13 and U16 was analyzed. Tennis performance was measured by using the ranking position on the Dutch national ranking list at U13 and U16. Regression analyses were conducted based on correlations between variables and tennis performance for boys and girls, separately. In boys U13, positive correlations were found between upper body power and tennis performance (R² is 25%). In girls, positive correlations between maturation and lower body power with tennis performance were found at U13. Early maturing players were associated with a better tennis performance (R² is 15%). In girls U16, only maturation correlated with tennis performance (R² is 13%); later-maturing girls at U13 had better tennis performances at U16. Measuring junior elite tennis players at U13 is important for monitoring their development. These measurements did not predict future tennis performance of junior elite tennis players three years later. Future research should focus on other aspects in order to predict tennis performance better.

Modeling Longitudinal Changes in 5 m Sprinting Performance Among Young Male Tennis Players

Year-to-year changes in sprinting in youth tennis players were examined in a mixed-longitudinal study (256 male players, aged 10–15 years: 993 measurements). Height (h), body mass (BM), lower limb explosive strength (LLES), and a 5-m sprint were measured over five years. During that period, players were classified as elite or sub-elite. To account for the repeated measurements within the individual nature of longitudinal data, multilevel random effects regression analyses were used. Sprint performance improved with age at each additional 1 year of age, thus predicting ∼.016 sec improvement in five-meter sprint time by all variables of the model. It was possible to predict the performance of elite tennis players in the 5-m sprint (sec) for elite players (1.1493 – (0.0159 ċ centered age) – (0.009 ċ BM) – (0.044 ċ LLES) and sub-elite players (1.1493 – (0.0159 ċ centered age) + 0.0135 – (0.009 ċ BM) – (0.044 ċ LLES) – (0.0557 ċ centered age). Sprint performance differences between elite and sub-elite players was related to longitudinal changes in body size and lower limb strength up until age 13.

Tennis: for the health of it!

Tennis is a sport with numerous health benefits for individuals of all ages. It is also a tremendously effective fitness activity. Regular participants experience a wide variety of health-related physical and mental benefits, from improved cardiovascular, metabolic, and bone health to improved agility, coordination, and even stress and anxiety management. Physicians and other health care professionals can play an important role in educating patients and the public about the health benefits of tennis as well as motivating them to take up this activity as part of an overall exercise prescription. Based on the scientific evidence available, it is difficult to find an activity that offers as wide a range of overall health benefits as tennis, and individuals who take up tennis reap tremendous rewards.

The effects of sensorimotor training on knee proprioception and function for patients with knee osteoarthritis: a preliminary report

Objective: To investigate the effects of a sensorimotor training programme in osteoarthritic patients.

Design: Randomized, single-blind, controlled trial.

Setting: Kinesiology laboratory at School of Physical Therapy.

Participants: A total of 60 patients were randomly assigned to the training group and the control group. Only 29 patients (training group, 15; control group, 14) completed the study.

Intervention: The training group underwent a sensorimotor training programme using a sling suspension system complemented by a routine physical therapy. The control group underwent a routine physical therapy.

Main measures: Active joint repositioning, functional testings, and self-reported function with the Western Ontario & McMaster Universities Arthritis Index before and after the eight-week intervention.

Results: There were significant differences between the two groups with respect to the improvement in proprioception as measured by active joint repositioning (the changes in the absolute error were 1.9± 1.7°, training group versus 0.1 ± 2.8°, control group (P<0.05), and in self-reported functional difficulty (33.2 ±35.1, training group versus 8.0± 10.2, control group; P<0.05)). There was no significant difference between the two groups in other outcomes.

Conclusion: A sensorimotor training using a sling suspension system improved the patients' proprioception in the knee joints and their self-reported function. Thus, these exercises may serve as an exercise programme for patients with knee osteoarthritis.

Health benefits for veteran (senior) tennis players

To explore the health benefits of tennis participation in veteran players and to identify future research needs, an electronic literature search using the Ovid (Cinhal, Medline, Sport Discus) library databases from 1966-2005 was undertaken. Specific search words were employed related to tennis, aging, exercise, health, and the psychophysiological systems. Public access internet search engines were also used (Google, PubMed), along with non-electronic searches of library holdings. There is ample research documenting the health benefits of regular participation in moderately intense aerobic activity. There have been research studies targeting veteran tennis players but most were cross sectional. No tennis related study successfully eliminated all confounding cross training effects. The health of veteran tennis players is improved by enhanced aerobic capacity, greater bone densities in specific regions, lower body fat, greater strength, and maintained reaction time performance in comparison with age matched but less active controls. However, it is not certain whether tennis alone can be a sole contributor to these physiological variables. Well controlled longitudinal research among elite veteran and novice older adult players is needed.

Hip and Knee Proprioception in Elite, Amateur, and Novice Tennis Players

OBJECTIVES

The purposes of this study were: (1) to show the differences of lower limb proprioception in three different groups of normal male subjects-elite, amateur, and novice tennis players-and between the skill-dominant and stance-dominant hip and knee and (2) to test the sensitivity of closed-chain reposition test in the three groups.

DESIGN

There were 22, 20, and 20 subjects in the three groups, respectively. Proprioception was tested with the closed-chain reposition method. Absolute error and variable error were calculated. One-way analysis of variance and Tukey's test were used to test the differences.

RESULTS

The proprioception of the hip joints of the elite players was significantly better than that of the other two groups in absolute error (P < 0.0167). In variable error analysis, the proprioception of the stance-dominant leg of the elite players was significantly better than that of the novice players (P < 0.0033).

CONCLUSIONS

Findings of this study supported that the proprioception of elite players was the best. The closed-chain reposition test had good discriminating power between the elite players and the others.

Longitudinal growth study of male Japanese junior high school athletes

The aim of this study was to establish the pattern of adolescent growth in height of male Japanese athletes, and to compare their growth with appropriate controls. The sample consisted of 126 baseball, 39 basketball, 83 soccer, and 53 volleyball players, and 36 nonathletes. The data were collected retrospectively in six public schools in Fukui Prefecture of Western Japan between 1970 and 1987. All subjects were measured at yearly intervals between the age of 6 and 18 years. The total number of measurement occasions for the 337 subjects amounted to 4,134. Athletes trained between 13 and 18 h/week. Individual growth patterns were determined by fitting Preece Baines model I to each individual's serial data. Various biological parameters were derived from the fitted curves. The results indicated that the average growth pattern of these adolescent athletes did not differ substantially from the control group. Volleyball players were significantly taller at 18 years (+3 cm) than the nonathletes (Student's t-test, P < 0.05). Soccer players showed a slight tendency towards late maturation with age at take-off and at peak velocity about half a year later than in nonathletes (Student's t-test, P < 0.05). The 2.3 cm gain in body height due to the later onset of the pubertal growth spurt in soccer players was counterbalanced by a 0.7 cm smaller prepubertal height and a 0.9 cm smaller adolescent gain, so that they ended up slightly, but not significantly, taller than the controls (+0.7 cm). The small differences in growth pattern observed between the nonathletes and the various sports suggest that, in contrast with top-level athletes, body size and maturation rate were not important selective factors in the various groups of athletes of the present study.

A comparison of cervical rotation in age-matched adolescent competitive swimmers and healthy males

Physical therapists routinely compare range of motion measurements with the opposite side and/or with a standard for "normal" range. However, "normal" range may vary in relation to the individual's occupational and recreational movement patterns. The purposes of this study were 1) to compare the range of active physiological cervical rotation in 14- to 17-year-old male competitive swimmers (N = 40) and controls (N = 40) and 2) to investigate the relationship between the freestyle stroke breathing pattern and differences in right and left cervical rotation in swimmers. Analysis of variance determined if a group difference existed in goniometric measurement of cervical rotation. The experimental group demonstrated a significantly greater mean range of total active cervical rotation right (p = 0.002) than the control group. Swimmers also demonstrated a significantly greater (p = 0.0002) range of rotation on their breathing side (mean difference of 5 degrees). It was concluded that the differences in physiological cervical rotation between swimmers and nonswimmers and between sides in the swimmers were influenced by the swimming activity. The clinician needs to consider the influence of activity when assessing range of motion.

Passive drag is still a good evaluator of swimming aptitude

The passive drag (Dp) of 218 competitive swimmers was studied and related to their performance level. To study this relationship, specific attention was given to anthropometric and joint laxity (JL) variations. The Dp was measured at 1.40 m.s-1, using a mechanical winch and a strain gauge with a load cell connected to a strain bridge. Swimmers were towed in a prone position holding their breath after a maximal inspiration. Buoyancy was evaluated by the hydrostatic lift (HL), i.e., the maximal weight just necessary to maintain the swimmer in a balanced position under the water after a maximal inspiration. The JL was assessed by a standard scoring system. The Dp was related mainly to the surface area (SA) (r = 0.73 and 0.53; P less than 0.01, for males and females, respectively). For a given SA, Dp was inversely related to the performance level. The JL explained 7% of the variability of Dp. On average, Dp measured after a maximal expiration, increases of about 22% SD 3% (P less than 0.01). This increase was related to individual vital capacities (r = 0.86, P less than 0.01). As Dp was mainly related to SA and HL, it is suggested that the body exerts a large pressure effect on the water. The contribution to performance might be related to the gliding phase of swimming.

Neuromuscular, metabolic and hormonal profiles of young tennis players and untrained boys

This study compared the neuromuscular, metabolic and hormonal profiles of trained prepubescent tennis players and an untrained group. The boys in the experimental group (n = 9; mean age +/- S.D. = 11.4 +/- 0.5 years) had participated in tennis training for 2.3 +/- 1.0 years and the boys in the control group (n = 9; mean age +/- S.D. = 10.9 +/- 0.4 years) were normal active volunteers. The tennis players were found to be physically more active than the controls when the comparison was made for either 1 year (4.9 +/- 1.8 vs 2.6 +/- 2.5 times per week; P less than 0.05) or for 1 week (3.4 +/- 1.2 vs 0.4 +/- 0.5 times; P less than 0.001) preceding the tests. Choice reaction time was significantly (P less than 0.01) shorter in the experimental group (258 +/- 16 ms) than in the control group (344 +/- 81 ms). Dropping height in the best drop jump was significantly (P less than 0.05) higher in the tennis players (0.46 +/- 0.19 m) than in the control boys (0.27 +/- 0.10 m). The tennis players had significantly lower oxygen consumption at the 'anaerobic threshold' than the controls (P less than 0.05). There were no significant differences between the groups in serum hormone levels. The small differences that existed may have been caused by active participation in sport by the tennis players.

Maximal static pressures and lung volumes in young female swimmers: one year follow-up

The relationship between the growth of lung volumes and the development of maximal static pressures was examined in a 1 year follow-up study of 17 female swimmers, initially less than 12 years of age. Lung volumes were measured by body plethysmography, and maximal static inspiratory and expiratory pressures were generated near residual volume, at functional residual capacity and near total lung capacity (TLC). The results were compared to the regressions obtained from cross-sectional data generated on 59 girls randomly selected from a local school. Height was similar in swimmers and controls. Vital capacity and total lung capacity increased during the year to exceed normal limits in 11 of 17 swimmers. The only significant increase of maximal static pressures during 1 year occurred in expiration near TLC in those swimmers initially less than 10 years of age, and all pressures fell within normal limits. We conclude that large lung volumes in swimmers cannot be accounted for by an increased ability to inflate and deflate the lung by the respiratory muscles.