Association of different types of playing surfaces with bone mass in growing girls

The aim of this cross-sectional study was to compare bone mass in young female athletes playing ball games on different types of playing surfaces. About 120 girls, 9–13 years of age (10.6 ± 1.5 years old Tanner I–III) were recruited and divided into prepubertal and pubertal groups. The sample represented 3 groups of athletes: soccer (N = 40), basketball (N = 40), and handball (N = 40); and 6 different playing surfaces (soccer – ground, soccer – artificial turf, basketball – synthetic, basketball – parquet, handball – synthetic, and handball – smooth concrete). Total and regional body composition (bone mass, fat mass, and lean mass) were measured by dual-energy X-ray absorptiometry (DXA). The mechanical properties of the surfaces (force reduction, vertical deformation, and energy return) were measured with the Advanced Artificial Athlete (Triple A) method. The degree of sexual development was determined using Tanner test. The pubertal group showed that soccer players on the ground, basketball players on synthetic, and handball players on smooth concrete had higher values of bone mineral content (BMC) and bone mineral density (BMD) (P < 0.05) than the soccer players on the artificial turf, basketball players on parquet, and handball players on synthetic. In conclusion, a hard playing surface, with less vertical deformation and force reduction, and greater energy return, is associated with higher levels of BMD and BMC in growing girls, regardless of the sport they practice.     

Isokinetic imbalance of hip muscles in soccer players with osteitis pubis

Abstract

In this study, we compared the isokinetic torques of hip flexors/extensors and abductors/adductors in soccer players suffering from osteitis pubis (OP), with normal soccer players. Twenty soccer male athletes with OP and 20 normal soccer athletes were included in this study. Peak torque/body weight (PT/BW) was recorded from hip flexor/extensor and abductor/adductor muscles during isokinetic concentric contraction modes at angular velocity of 2.1 rad · s^?1, for both groups. The results showed a significant difference between the normal and OP groups for hip flexors (P < 0.05). The normal group had significant, lower PT/BW value than the OP group for their hip flexors (P < 0.05). The hip flexor/extensor PT ratio of OP affected and non-affected limbs was significantly different from that of normal dominant and non-dominant limbs. There were no significant differences between the normal and OP groups for hip extensor, adductor and abductor muscles (P > 0.05). Regarding the hip adductor/abductor PT ratio, there was no significant difference between the normal and OP groups of athletes (P > 0.05). The OP group displayed increase in hip flexor strength that disturbed the hip flexor/extensor torque ratio of OP. Therefore, increasing the hip extensor strength should be part of rehabilitation programmes of patients with OP.     

Soccer and Zumba as health-promoting activities among female hospital employees: a 40-weeks cluster randomised intervention study

Abstract

The aim of this study was to evaluate the physiological effects of soccer and Zumba among female hospital employees during a 40-week intervention period. Hospital employees (n = 118) were cluster-randomised to either a soccer group (n = 41), a Zumba group (n = 38) or a control group (n = 39). Both training groups were encouraged to perform 1-h training sessions twice a week outside working hours throughout the 40 weeks. Maximal oxygen uptake (VO₂ max), blood pressure and body composition were measured and blood samples collected before and after the intervention period. Using intention-to-treat analyses, the Zumba group improved VO₂ max compared to the control group (2.2 mL · kg^?1 · min^?1, 95% CI, 0.9, 3.5, P = 0.001), with no significant increase in the soccer group (1.1 mL · kg^?1 · min^?1, 95% CI, ?0.2, 2.4, P = 0.08). Both intervention groups reduced total body fat mass and fat percentage compared to the control group (P < 0.01). In the soccer group, but not the Zumba group, a significant difference in lower limb bone mineral density and bone mineral content was observed in comparison to the control group (P < 0.01). Furthermore, the soccer group, but not the Zumba group, had increased plasma osteocalcin (6.6 µg · L^?1, 95% CI, 2.2, 11.0, P < 0.01) and decreased plasma leptin (?6.6 µg · L^?1, 95% CI, ?12.5, ?0.7, P < 0.05) compared to the control group. The present study suggests that workplace-initiated soccer and Zumba training comprising 1–2 sessions per week outside working hours may promote physiological health among female hospital employees.     

The evaluation of small-sided games as a talent identification tool in highly trained prepubertal soccer players

The aim of this study was to evaluate physiological and technical attributes of prepubertal soccer players during multiple small-sided games (SSGs), and determine if SSGs can act as a talent identification tool. Sixteen highly trained U10 soccer players participated and separated into two groups of eight. Each group played six small-sided (4 vs. 4) matches of 5-min duration. Each player was awarded total points for the match result and goals scored. A game technical scoring chart was used to rate each player’s performance during each game. Time-motion characteristics were measured using micromechanical devices. Total points had a very large significant relationship with game technical scoring chart (r = 0.758, P < 0.001). High-speed running distance had a significantly large correlation with game technical scoring chart (r = 0.547, P < 0.05). Total distance covered had a significant and moderate correlation with game technical scoring chart (r = 0.545, P < 0.05) and total points (r = 0.438, P < 0.05). The results demonstrated a large agreement between the highest-rated players and success in multiple SSGs, possibly due to higher-rated players covering larger distances in total and at high speed. Consequently, multiple SSG could be used to identify the more talented prepubertal soccer players.     

Effect of contact and no-contact small-sided games on elite handball players

This study aimed to investigate the effect of contact (C-SSG) and no-contact (NC-SSG) handball small-sided games (SSGs) on motion patterns and physiological responses of elite handball players. Twelve male handball players performed 10 C-SSG and 10 NC-SSG while being monitored through the heart rate (HR) and rate of perceived exertion (RPE) as physiological responses and time-motion activities profile using video-match analysis. Both game conditions resulted in similar HR responses (P > 0.05), but the NC-SSG led to a higher RPE scores. The time-motion activity analysis featured NC-SSG with a greater amount of walking (855.6 ± 25.1 vs. 690.6 ± 35.2 m) and backward movements (187.5 ± 12.3 vs. 142.5 ± 8.7 m) combined with fast running (232.3 ± 8.5 vs. 159.7 ± 5.7 m) and sprinting (79.5 ± 4.7 vs. 39.7 ± 3.7 m) activities (P < 0.001). Conversely, C-SSG had a higher percentage of jogging and sideway movements associated with greater frequency of jumping (0.87 ± 0.09 vs. 0.31 ± 0.06 nr) and physical contact (1.82 ± 0.55 vs. 0.25 ± 0.03 nr) events (P < 0.001). No between-regimen differences were found for the number of throws (P = 0.745). In addition, the RPE was significantly correlated with fast running relative distances (r = 0.909, P < 0.001) and sprinting relative distances (r = 0.939, P < 0.001). In conclusion, this investigation showed that both C-SSG and NC-SSG in team handball can effectively represent specifically oriented exercises, according to the sport-task and the performance demands.     

Morning–evening difference of team-handball-related short-term maximal physical performances in female team handball players

This study investigated the two different time-of-day effect on team-handball-related short-term maximal physical performances. At two different time-of-day, fifteen young female team handball players performed different physical tests: HandGrip (HG) test, Ball-Throwing Velocity (BTV) test, Modified Agility T-test (MAT) and Repeated Shuttle-Sprint and Jump Ability (RSSJA) test. Rating of perceived exertion (RPE) scale was determined following the termination of the last test. Measurements were performed at two separate testing sessions (i.e., in the morning (7:00–8:30 h) and in the early evening (17:00–18:30 h)) in a randomised and counter-balanced setting on non-consecutive days. The results showed that HG (P = 0.0013), BTV (P = 0.0027) and MAT (P < 0.001) performances were better in the evening compared with the morning. During RSSJA, both best and mean sprint times were shorter in the evening compared to the morning (P < 0.001). Moreover, during the latter test, mean jump performance was higher in the evening compared to the morning (P = 0.026). However, there was no morning–evening difference in the best jump performance during RSSJA. Likewise, jump performance decrement was not affected by the time-of-day of testing. On the other hand, RPE fluctuated, with morning nadirs and afternoon/early evening highest values. The findings suggest that in female team handball players, team-handball-related short-term maximal physical performances were better in the afternoon than in the morning.     

Higher bone mass in prepubertal and peripubertal female footballers

Objectives: The main aim of this study was to compare the bone mass of female football players with controls of different pubertal stages. Methods: Sixty five girls aged 8–14 years (10.14?±?0.1, Tanner stages I–IV) participated in the study. Twenty participants were prepubertal (10 prepubertal control) and 45 peripubertal (15 peripubertal control). All footballers trained two days per week while the control group did not perform regular physical activity outside of school. Body composition was assessed by Dual-energy X-ray absorptiometry. Analysis of covariance was performed to evaluate differences in lean and bone masses. Results: Significant differences in lower-body extremities lean mass (LLM) between peripubertal groups were found (P?P?P?Conclusion: Female footballers showed higher bone and lean masses compared to control counterparts; these differences are already detectable at prepubertal ages and more consistent after pubertal spurt.     

Swimming and peak bone mineral density: A systematic review and meta-analysis

This meta-analysis aims to determine the effects of regular swimming on bone mineral density (BMD) in young adults (18–30 years). A systematic search was performed in Pubmed, SPORTDiscus and the Cochrane Library from the earliest possible year to March 2016. Swimmers were compared to non-athletic controls (CG) and to high-impact athletes (HIGH). Effect sizes with the Hedges g in random effects models were developed. Fourteen studies met the inclusion criteria and were included in the meta-analyses. Swimmers presented similar BMD values to CG in whole-body (g = ?0.20; P = 0.251), femoral neck (g = ?0.05; P = 0.818) and lumbar spine (g = 0.18; P = 0.492); and lower BMD in the whole-body (g = ?1.21; P < 0.001), femoral neck (g = ?1.51; P < 0.001) and lumbar spine (g = ?0.84; P = 0.017) than the HIGH. For the whole-body differences, the higher the latitude the smaller the differences between swimmers and HIGH (B = 0.10; P = 0.001). For the femoral neck differences, age also seemed to reduce the differences between groups (B = 0.19; P = 0.020). Young adult swimmers present similar BMD values than CG and lower values than HIGH.     

Core stability training on lower limb balance strength

This study aimed to assess the effects of core stability training on lower limbs’ muscular asymmetries and imbalances in team sport. Twenty footballers were divided into two groups, either core stability or control group. Before each daily practice, core stability group (n = 10) performed a core stability training programme, while control group (n = 10) did a standard warm-up. The effects of the core stability training programme were assessed by performing isokinetic tests and single-leg countermovement jumps. Significant improvement was found for knee extensors peak torque at 3.14 rad · s^?1 (14%; P < 0.05), knee flexors peak torque at 1.05 and 3.14 rad · s^?1 (19% and 22% with P < 0.01 and P < 0.01, respectively) and peak torque flexors/extensors ratios at 1.05 and 3.14 rad · s^?1 (7.7% and 8.5% with P < 0.05 and P < 0.05, respectively) only in the core stability group. The jump tests showed a significant reduction in the strength asymmetries in core stability group (?71.4%; P = 0.02) while a concurrent increase was seen in the control group (33.3%; P < 0.05). This study provides practical evidence in combining core exercises for optimal lower limbs strength balance development in young soccer players.     

Anthropometric and physical performance characteristics of top-elite,elite and non-elite youth female team handball players

In order to maximise the potential for success, developing nations need to produce superior systems to identify and develop talent, which requires comprehensive and up-to-date values on elite players. This study examined the anthropometric and physical characteristics of youth female team handball players (16.07 ± 1.30 years) in non-elite (n = 47), elite (n = 37) and top-elite players (n = 29). Anthropometric profiling included sum of eight skinfolds, body mass, stature, girths, breadths and somatotype. Performance tests included 20 m sprint, counter-movement jump, throwing velocity, repeated shuttle sprint and jump ability test, and Yo-Yo Intermittent Recovery Test Level 1. Youth top-elite players had greater body mass, lean mass, stature, limb girths and breadths than elite and non-elite players, while only stature and flexed arm were higher in elite compared to non-elite players (all P < 0.05). Sum of skinfolds and waist-to-hip ratio were similar between groups (P > 0.05). Top-elite performed better in most performance tests compared to both elite and non-elite players (P < 0.05), although maximal and repeated 10 m sprints were similar between playing standards (P > 0.05). Elite outperformed non-elite players only in throwing velocity. The findings reveal that non-elite players compare unfavourably to top-elite international European players in many anthropometric and performance characteristics, and differ in a few characteristics compared to elite European club team players. This study is useful for emerging team handball nations in improving talent identification processes.     

Acute and chronic effects of foam rolling vs eccentric exercise on ROM and force output of the plantar flexors

Foam rolling and eccentric exercise interventions have been demonstrated to improve range of motion (ROM). However, these two modalities have not been directly compared. Twenty-three academy soccer players (age: 18 ± 1; height: 1.74 ± 0.08 m; body mass: 69.3 ± 7.5 kg) were randomly allocated to either a foam rolling (FR) or eccentric exercise intervention designed to improve dorsiflexion ROM. Participants performed the intervention daily for a duration of four weeks. Measurements of dorsiflexion ROM, isometric plantar flexion torque and drop jump reactive strength index were taken at baseline (pre-intervention) and at three subsequent time-points (30-min post, 24-hours post and 4-weeks post). A significant time x group interaction effect was observed for dorsiflexion (P = 0.036), but not for torque or reactive strength index. For dorsiflexion, there was a significant increase in both acute (30-min; P < 0.001) and chronic (4-week; P < 0.001) ROM for the eccentric group, whilst FR exhibited only an acute improvement (P < 0.001). Eccentric training would appear a more efficacious modality than foam rolling for improving dorsiflexion ROM in elite academy soccer players.     

Three-dimensional kinematics and ground reaction forces during the instep and outstep soccer kicks in pubertal players

Abstract

The purpose of the present study was to compare the three-dimensional kinematics of the lower extremities and ground reaction forces between the instep kick and the kick with the outside area of the foot (outstep kick) in pubertal soccer players. Ten pubertal soccer players performed consecutive kicking trials in random order after a two-step angled approach with the instep and the outstep portion of the foot. Three-dimensional data and ground reaction forces were measured during kicking. Paired t-tests indicated significantly higher (P < 0.05) ball speeds and ball/foot speed ratios for the instep kick compared with the outstep kick. Non-significant differences in angular and linear sagittal plane kinematic parameters, temporal characteristics, and ground reaction forces between the instep and outstep soccer kicks were observed (P > 0.05). In contrast, analysis of variance indicated that the outstep kick displayed higher hip internal rotation and abduction, knee internal rotation, and ankle inversion than the instep kick (P < 0.05). Our results suggest that the instep kick is more powerful than the outstep kick and that different types of kick require different types of skill training.     

Bone mineral density in top level male athletes of different sports

The purpose of this study was to determine the influence of muscle strength, trainingspecific and anthropometric parameters on bone mineral density (BMD) in male top athletes of different sports in comparison to untrained controls. BMD was measured by dual energy X-ray absorptiometry in 173 males, aged 18 to 31 years. Of these, 104 were athletes (runners, n = 21; cyclists, n = 12; triathletes, n = 18), heavy athletes (HA, judo and wrestling, n = 28), and team sport athletes (TS, handball, soccer, basketball, volleyball, n = 25); 44 were unspecifically trained sport students (STU); and 25 were untrained controls (UT). Sport- and group-specific differences were found in anthropometric but not strength parameters. Marked sport- and group-specific differences were found for BMD at lumbar spine (LSP) and the femoral sites (FEM). Group-specific effects on BMD were clearest when calculating percentual differences between BMD of athletes and UT: In group I (HA, TS, and STU), BMD at LSP and FEM were significantly (p < .01) higher compared to UT; in group II (R and TRI), BMD at FEM but not at LSP was higher compared to UT (p <.01); and in group III (C), no BMD value was significantly different from UT. Multiple regression analysis revealed lean body mass to be the strongest predictor for BMD at LSP and FEM. We conclude that mechanical loads have strong effects on bone adaptation. Sport-specific and body region-specific effects have to be taken into account for evaluation of osteogenic effects of exercise. Particularly dynamic sports with short, high, and multidimensional loads have the strongest effects on bone formation, independent of training quantity.     

Bone mineral density and body composition in elite female golf and netball players

Abstract

The aim of this study was to compare bone density and body composition measurements in women participating in elite-level netball and golf, two sports with contrasting loading characteristics. Bone mineral density (BMD) and body composition were measured using dual-energy X-ray absorptiometry (DXA) in 14 state-level netball players (20.8±3.4 years), 11 single-digit handicap golf players (22.4±2.1 years) and a control group (n=18) not training for sport (22.6±3.6 years). Trunk extensor endurance and grip strength were also measured using the Sorensen test and hand-grip dynamometry respectively. Netball players had significantly higher total body, lumbar spine and hip BMD than the golf players (P<0.001) and control subjects (P<0.001). The golf players had higher BMD than the control subjects only in the lumbar spine (P<0.05). The netball players were significantly taller than the golf players and control group (P<0.01) and had a higher body mass than the control group (P<0.001). After adjustment for body height and mass, the BMD values in the netball players remained significantly higher than the control subjects at all sites (P<0.01), while the golf players had significantly higher lumbar spine BMD than the controls (P<0.05). Elite-level netball participation is associated with increased total body, hip and lumbar spine BMD, while this response was only evident in the lumbar spine in elite golf players. The contrasting loading characteristics of these sports may be reflected in the site-specific differences in BMD when compared to non-athletic control subjects.     

Total,regional and unilateral body composition of professional English first-class cricket fast bowlers

There have been few reports of advanced body composition profiles of elite fast bowlers in the sport of cricket. Therefore, the aim of the current study was to determine total, regional and unilateral body composition characteristics of elite English first-class cricket fast bowlers in comparison with matched controls, using dual-energy X-ray absorptiometry (DXA). Twelve male fast bowlers and 12 age-matched, non-athletic controls received one total-body DXA scan. Anthropometric data were obtained as well as left and right regional (arms, legs and trunk) fat mass, lean mass and bone mineral content. Fast bowlers were significantly taller and heavier than controls (P < 0.05). Relative to body mass, fast bowlers possessed greater lean mass in the trunk (80.9 ± 3.7 vs. 76.7 ± 5.9%; P = 0.047) and bone mineral content in the trunk (2.9 ± 0.3 vs. 2.6 ± 0.3%; P = 0.049) and legs (5.4 ± 0.5 vs. 4.6 ± 0.6%; P = 0.003). In the arm region, fast bowlers demonstrated significantly greater unilateral differences in bone mineral content (10.6 ± 6.6 vs. 4.5 ± 3.9%; P = 0.012). This study provides specific body composition values for elite-level fast bowlers and highlights the potential for muscle and bone imbalances that may be useful for conditioning professionals. Our findings also suggest beneficial adaptations in body composition and bone mass in fast bowlers compared with their non-athletic counterparts.     

Effects of tapering on physical match activities in professional soccer players

ABSTRACT

This study aimed to examine: (i) the effect of decreasing training load (TL) during taper weeks on physical match activities in professional soccer players, and (ii) to disclose the relationship between weekly TL and physical match activities. Rating of perceived exertion was collected after each training session and match to quantify the TL in 19 professional players over 17 standard and 7 taper weeks during the season. Physical match activities were quantified by a computerised match analysis system and compared between standard training and taper weeks. Compared to standard weeks, the duration and frequency of training sessions during the taper weeks decreased (?21.7% and ?18.8%, respectively; P < 0.01) with no change in intensity (?4.8%; P = 0.09). Consequently, the weekly TL decreased during the taper weeks (?25.5%; P < 0.01). Increases in distance covered by intense running (+15.1%; P < 0.05), high-intensity running (HIR) (+15.7%; P < 0.01), number of sprints (+17.8%; P < 0.05) and number of high-speed runs (+15.7%; P < 0.05) were observed during the seven matches played after the taper weeks. High relationships were observed between TL and HIR distance covered, number of HIR and number of sprints (r = ?0.53; r = ?0.55; r = ?0.65, respectively; P < 0.01). Decreasing TL during taper weeks by reducing training duration and frequency but maintaining intensity was associated with an increase in physical activities during matches. However, it needs to be determined whether tapering or other match factors led to the changes in match activity.     

Comparative efficacy of active recovery and cold water immersion as post-match recovery interventions in elite youth soccer

ABSTRACT

The current study compared cold-water immersion (CWI) and active recovery (AR) to static stretching (SS) on muscle recovery post-competitive soccer matches in elite youth players (n = 15). In a controlled crossover design, participants played a total of nine competitive soccer games, comprising three 80 minute games for each intervention (SS, CWI and AR). Muscle oedema, creatine kinase (CK), countermovement jump performance (CMJA) and perceived muscle soreness (PMS) were assessed pre-, immediately post-, and 48 hours post-match and compared across time-intervals and between interventions. Following SS, all markers of muscle damage remained significantly elevated (P < 0.05) compared to baseline at 48 hours post-match. Following AR and CWI, CMJA returned to baseline at 48 hours post-match, whilst CK returned to baseline following CWI at 48 hours post-match only. Analysis between recovery interventions revealed a significant improvement in PMS (P < 0.05) at 48 hours post-match when comparing AR and CWI to SS, with no significant differences between AR and CWI observed (P > 0.05). Analysis of %change for CK and CMJA revealed significant improvements for AR and CWI compared to SS. The present study indicated both AR and CWI are beneficial recovery interventions for elite young soccer players following competitive soccer matches, of which were superior to SS.     

A longitudinal study of multidimensional performance characteristics related to physical capacities in youth handball

Abstract

Longitudinal research provides valuable information about change and progress towards elite performance. Unfortunately, there is a lack of longitudinal research in handball. In this study, 94 youth handball players (oldest group: n = 41; age 15–17 and youngest group: n = 53; age 13–15) were followed over a three-year period. Repeated Measures ANCOVA was conducted to reveal longitudinal changes in anthropometry and physical performance between elite and non-elite players, controlling for maturation. Maturation effects were found for anthropometry (P < 0.01) and some physical performance measures in strength and speed (P < 0.05). The lack of significant interaction effects revealed that during the three years of the study the elite players did not improve their physical performance more rapidly than the non-elites. Furthermore, they had a similar anthropometric profile to the non-elites. Elite players performed better on the Yo-Yo Intermittent Recovery test (P < 0.01; on average 24.0 in the youngest group and 25.2% in the oldest group over the three years) and on the speed and coordination items (P < 0.05; shuttle run: 3.6 and 5.1%; cross hopping: 11.0 and 14.8%, handball-specific shuttle run: 7.6 and 7.7%; slalom dribble test: 10.7 and 8.9%; sprint 30 m: 4.9 and 3.9%). Additionally, Yo-Yo performance and coordination with and without a ball were the most discriminating factors between the playing levels. In conclusion, youth coaches and scouts within team handball should recognise the importance of good skills and an excellent endurance for talent identification purposes.     

Bone mass in girls according to their BMI,VO2 max,hours and years of practice

The accumulation of bone mass during puberty is related with bone health in adulthood. This accumulation is influenced by diverse factors such as body mass index (BMI), maximal oxygen uptake (VO₂ max), hours of training and years of sport practice. For this reason, the objective of this study is to analyse the influence of these variables on bone mass in young female athletes. The sample is formed of 120 healthy girls with ages between 9 and 13 (11.32?±?1.6?years old), divided into two groups depending on their BMI, VO₂ max, hours of training and years of sport practice. The participants completed a series of tests to evaluate level of sexual development, body composition (fat mass, lean mass and bone mass) and physical condition. The results show higher values of total lean mass, total fat mass and percentage of body fat in the groups with higher BMI in prepubertal girls and pubertal girls (p?2 max, in the prepubertal group, girls with lower VO₂ max had higher values of total fat mass (p?p?2 max also showed a higher total fat mass (p?相似文献   

Biomechanical mechanisms of jumping performance in youth elite female soccer players

ABSTRACT

We aimed to determine key biomechanical parameters explaining age-related jumping performance differences in youth elite female soccer players. Multiple biomechanical parameters from countermovement (CMJ) squat (SJ) and drop (DJ) jump testing of elite female soccer players (n = 60) within the same national training centre were analysed across ages 9-11y, 12-14y and 15-19y. Effects of age group and jump type on jump height were found, with the older jumping higher than the younger groups in all jumps (P < 0.05). For DJ, higher reactive strength index was found for older, compared to each younger group (P < 0.001). For CMJ and SJ, peak power was the most decisive characteristic, with significant differences between each group for absolute peak power (P < 0.0001) and body-weight-normalised peak power in CMJ (57 ± 7W/kg, 50 ± 7W/kg, 44.7 ± 5.5W/kg; P < 0.05) and between the older and each younger group in SJ (56.7 ± 7.1W/kg, 48.9 ± 7.1W/kg, 44.6 ± 6W/kg; P < 0.01). Age-related differences in jumping performance in youth elite female soccer players appear to be due to power production during standing jumps and by the ability to jump with shorter ground contact times during reactive jumps.