The Reliability of Linear Speed with and without Ball Possession of Pubertal Soccer Players

Reliable fitness tests with low day-to-day and trial-to-trial variation are a prerequisite for tracking a player's performance or for identifying meaningful changes in training interventions. The present study examined the inter- and intra-session reliability of 30 m linear speed with and without ball possession as well as the reliability of a specific performance index of pubertal soccer players. A total of 40 pubertal (14.87 ± 1.23 years old) male soccer players performed two testing sessions (test-retest) separated by 72 h. Both testing sessions included a protocol consisting of two maximal trials of 30 m linear speed with and without ball possession. A performance index, indicating the difference between the two speed tests, was also calculated using two different equations (delta value and percentage value). The relative and absolute inter-session reliabilities were good/high for all testing variables (ICC = 0.957-0.995; SEM% = 0.62-8.83). There were also good/high relative and absolute intra-session reliabilities observed for all testing variables (ICC = 0.974-0.987; SEM% = 1.26-6.70%). According to the Bland-Altman plots, the differences between test-retest and trials for all observations were within the defined 95% limits of agreement. The reliable testing protocols and performance index for the evaluation of linear speed with and without ball possession, observed in this study, may be used in speed monitoring and training planning of pubertal soccer players.

A Chair-Based Music-Kinetic Combined Exercise Program as an Alternative Approach for Increasing Health, Functional Capacity, and Physical Fitness Indices in Middle-Aged Pre-Menopausal Women

Lately, chairs have been widely used as a cheap, easily accessible, safe, and effective training means in different settings (e.g., in gyms, the house, workplaces, and in rehabilitation). This study investigated the effectiveness of a 10-week chair-based music-kinetic integrated combined exercise program on health, functional capacity, and physical fitness indicators of middle-aged pre-menopausal women. A total of 40 healthy women (40-53 years) were assigned to two groups: exercise (EG) and control (CG). The EG followed a 10-week (3 times/weekly; 30 training sessions) chair-based exercise program including aerobic dance, flexibility, coordination, and strength exercises with body weight or auxiliary means. Selected indicators of health, functional capacity, and physical fitness were evaluated before and after the 10 weeks. Following the program, the EG significantly reduced their body fat (-2.5%), blood pressure (by -4.5 to -5.5%), the time during the timed up-and-go (TUG) test (by -10.27%), heart rate (by -6.35 to -13.78%), and the rate of perceived exertion (by -24.45 to -25.88%), while increasing respiratory function (3.5-4%), flexibility (12.17%), balance (50.38-51.07%), maximal handgrip strength (10-12.17%), and endurance strength (43.87-55.91%). The chair-based combined music-kinetic exercise program was effective and could be safely used in different settings to improve health, functional capacity, and physical fitness in middle-aged women.

Sport-Related Effect on Knee Strength Profile during Puberty: Basketball vs. Soccer

The present study examined and compared the isokinetic peak torque and the reciprocal ratios of the knee joint between young basketball and soccer players. An amount of 100 soccer and 100 basketball players took part in this study and were separated into five equal groups (n = 20), according to their chronological age (12, 13, 14, 15, and 16 years old). The absolute concentric (CON) and eccentric (ECC) peak torque of the knee flexor and extensor muscles (at 60°/s, 180°/s) were assessed using a Cybex Norm dynamometer, and the relative peak torque (per unit of body mass), as well as the conventional (CON/CON; ECC/ECC) and functional (CON/ECC; ECC/CON) ratios, were calculated. Data analysis indicated that the basketball players had higher absolute peak torque values than the soccer players throughout their developmental ages (p < 0.05). When the isokinetic peak torque values were normalized relative to body mass, no differences were observed between basketball and soccer players in any age group (p > 0.05). Additionally, no differences were observed in conventional and functional ratios between soccer and basketball players (p > 0.05). In conclusion, it appears that, during developmental ages (12-16 years old), the isokinetic strength profile (independent of body mass affecting absolute values) of knee extensor and flexor muscles develops similarly in basketball and soccer players.

An Enjoyable Workplace Combined Exercise Program for Health Promotion in Trained Employees: Yoga, Pilates, and Circuit Strength Training

Corporate wellness has become an important public health priority through the designing and implementation of different workplace exercise interventions. The objectives of this study were to investigate: (a) the effectiveness of a 4-month workplace combined yoga, Pilates, and circuit strength training program (outside work shift) on health indices, functional capacity, and physical fitness in office employees; and (b) the employees' enjoyment following the program. Fifty physically active office employees (26-55 years old) were equally divided into training (TG) and control groups (CG). The TG followed a 4-month (3 times/week, 50-60 min/training) combined yoga, Pilates, and circuit strength training program. Health indices (body composition, body mass, circumferences, musculoskeletal pains), functional capacity (flexibility, balance), and physical fitness (strength, aerobic capacity) were measured before and after the 4-month time period. After the completion of the program, the TG participants' enjoyment was assessed. The TG significantly improved (p < 0.001) all health, functional capacity (11.3-82.0%), and physical fitness indices (33.9%), except for aerobic capacity, which did not change (p > 0.05). Furthermore, a great percentage of employees (84%) reported high levels of enjoyment. This program could be effectively and safely used in workplace settings as an enjoyable intervention to improve specific health, functional capacity, and physical fitness indices in office employees.

Can maximal handgrip strength and endurance be improved by an 8-week specialized strength training program in older women? A randomized controlled study

Maximal handgrip strength and endurance are important indicators of upper limb function in older adults. Up to now, there is insufficient information regarding the efficacy of specialized strength training programs for improving handgrip strength. The purpose of this study was to investigate the effectiveness of an 8-week specialized handgrip strength training program on maximal handgrip strength and endurance in healthy older women. A randomized controlled trial was performed. Thirty-six healthy older women (>65 years) were randomly divided into a training group (TG) (n = 18) and a control group (CG) (n = 18). The TG participated in an 8-week specialized handgrip strength training program using rubber balls and hand grippers (2 training sessions/week, 10-15 min, 8-15 repetitions/set, 4-6 total sets/session). Prior to and after the completion of the program, maximal handgrip strength and dynamic endurance (indices: repeated maximal repetitions and percentage change in handgrip strength between first and last 6 repetitions) were assessed in both hands. Repeated measures MANOVA results indicated that maximal handgrip strength (+9.3%-10.4%) and strength values during repeated maximal repetitions (+14% to 27%) significantly increased in TG (p < 0.001), while the percentage change in handgrip strength between the first and last 6 repetitions decreased significantly (-6%) (p < 0.05), irrespective of the tested hand. The results of this study showed that an 8-week specialized handgrip strength training program can be used effectively by athletic trainers, physical and hand therapists to counteract the detrimental effects of the aging process on maximal handgrip strength and endurance in older adults.

Strength Training Induces Greater Increase in Handgrip Strength than Wrestling Training per se

This study investigated the effectiveness of a specialized strength training program on maximal handgrip strength in young wrestlers. 72 young wrestlers (36 children: 8-10 years-old and 36 adolescents:13-15 years-old) participated in the present study. Both age-categories were assigned into a training group (18 children and 18 adolescents) and a control group (18 children and 18 adolescents). The training groups, in conjunction with the wrestling training performed a 4-month (2 sessions/week) specialized handgrip training program. Maximal handgrip strength was evaluated pre, at the intermediate (2 months) and at the completion of the program (4 months). Maximal handgrip strength values increased during the intermediate and post-training measurements compared to pre-training measurement in training and control groups (p<0.001). No significant differences were observed on pre-training and intermediate measurements between groups, while significant differences were observed during the post-training measurement. Training group exhibited significantly (p<0.01) greater maximal handgrip strength values than the control group irrespective of age-category and hand-preference. A 4-month handgrip strength training program, incorporated into the conventional wrestling training, provokes greater adaptations in maximal handgrip strength than the wrestling training per se. For greater handgrip training adaptations are required more than 14 specialized handgrip training-sessions.

Effects of whole-body vibration training frequency on neuromuscular performance: a randomized controlled study

This study compared the efficacy of two whole-body vibration (WBV) protocols with equal training volume and different frequency of training sessions/week on body composition and physical fitness. Sixty male air force cadets (age: 20.5±1.4 years) were randomly assigned to a lower frequency (Lf-WBV), a higher frequency (Hf-WBV) or a control group (CG). The training volume was equated (20 training sessions) between the two WBV groups, but the number of weekly training sessions was different. The Lf-WBV group trained three times per week, the Hf-WBV group trained five times per week, while the CG did not perform any training. Each training session, for both groups, included 10 sets x 1 min with 1 min rest of WBV on a synchronous vibration platform (25-35 Hz, 4-6 mm). Body composition, flexibility, maximal strength, 30 m sprint time, squat jump (SJ) and countermovement jump (CMJ) performance, Wingate test performance, and 20 m shuttle run performance were evaluated before and after training. Only the Hf-WBV group demonstrated an increase in flexibility (+7%; p<0.01; d=0.33) and maximal strength (+10%; p=0.016; d= 0.59), and a significant reduction in fat mass (-6.2%; p<0.01; d=0.21). SJ performance improved to a similar extent in both Hf-WBV and Lf-WBV groups (+7%; p<0.01; d=0.32). There were no changes in any parameter in the CG. In conclusion, only the condensed weekly WBV protocol was effective in improving body composition, flexibility, lower limb strength and power in young active individuals. The WBV protocol with the higher dispersion of training sessions per week (lower training frequency/week) improved SJ performance but did not have any effect on body composition, flexibility, or maximal strength.

Strength Profile of Hip Abductor and Adductor Muscles in Youth Elite Soccer Players

The main objective of this study was to provide an extensive isokinetic profile of the hip joint in youth soccer players, where the literature is limited. Additionally, this study investigated the effect of age on isokinetic peak torque values of hip abductor and adductor muscles and on reciprocal muscle group torque ratios in youth soccer players at different angular velocities (30 vs. 90o/s) and muscle actions (concentric vs. eccentric). Sixty young elite male soccer players were assigned into three equal groups (n = 20): children, young adolescents and older adolescents, and performed five maximal concentric and eccentric hip-abductions and adductions at 30o/s and 90o/s. The results showed a significant increase (p < 0.05) in peak torque values from childhood to adolescence, with the exception of young adolescents vs. older adolescents where no differences were observed. The reciprocal ratios were not affected by age, but improved with an increase in angular velocity with the exception of the CON/ECC ratio that was higher at 30o/s. The data presented in this study provide an extensive isokinetic profile of hip abductor and adductor muscle strength in youth soccer players to assist both coaches and sports medicine professionals in strength monitoring and training.

The effects of resisted sled-pulling sprint training on acceleration and maximum speed performance

AIM

The purpose of the present study was to examine the effects of resisted (RS) and un-resisted (US) sprint training programs on acceleration and maximum speed performance.

METHODS

Twenty-two male students (age 20.1+/-1.9 y, height 1.78+/-7 cm, and weight 73+/-2 kg) completed RS (n=11) or US (n=11) sprint training programs. The RS group followed a sprint-training program with 5 kg sled pulling and the US group followed a similar sprint-training program without sled pulling. The training program consisted of 4x20 m and 4x50 m maximal runs, and was applied 3 times/week for 8 weeks. Before and after the training programs the subjects performed a 50 m run and the running velocity of 0(-1)0 m, 10(-2)0 m, 20-40 m and 40-50 m was measured. In addition, stride length and stride frequency were evaluated at the 3(rd) stride in acceleration phase and between 42-47 m in maximum speed phase.

RESULTS

The RS improved running velocity in the run sections 0(-1)0 m and 0(-2)0 m, while in US group the running velocity in all run sections in acceleration phase remained unchanged (p>0.05). In contrast, RS training had no effect on running velocity in maximum speed phase, whereas US improved running velocity in 20-40 m, 40-50 m, and 20-50 m run sections (p<0.05). Stride rate increased only after RS in acceleration phase (+7.1+/-2.9%; p<0.05), whereas stride length increased only after US in maximum speed phase (+5.5+/-2.5%; p<0.05).

CONCLUSION

Sprint training with 5 kg sled pulling for 8 weeks improves acceleration performance (0(-2)0), while un-resisted sprint training improves performance in maximum speed phase (20-40) in non-elite athletes. It appears that each phase of sprint run demands a specific training approach.

Reliability of a practicable EMG-moment model for antagonist moment prediction

Although the use of practicable EMG-moment models for knee joint moment prediction appears promising, the repeatability of the estimated forces remains unclear. The purpose of this study was to apply an EMG-moment model to predict the antagonist moment of the knee flexors (Mflx) during maximal isometric knee extension efforts. Nine healthy males performed maximal isometric knee extension and flexion contractions at 0 degrees , 45 degrees and 90 degrees angles with recordings of the net moment and EMG of thigh muscles. Calibration knee flexion efforts were performed at different levels of intensity and the resulting EMG-moment curves were fitted using second-order polynomials. The polynomials were then used to predict Mflx. This procedure was repeated a week after. The results indicated non-significant differences in test-retest Mflx. Intraclass correlation coefficients ranged from 0.852 to 0.912 indicating high test-retest reliability of the estimated Mflx. For isometric contractions, the present model is suitable as a method to estimate antagonist muscle moments.

Combined effects of age and maturation on maximum isometric leg press strength in young basketball players

AIM

Muscular strength of the leg extensor muscles in children can be affected by several factors such as age, sexual maturation, body mass and training status of the subjects. The purpose of the study was to examine maximal isometric strength characteristics of young male basketball players taking into consideration the combined effects of chronological age and sexual maturation.

METHODS

One hundred and twenty male basketball players, aged from 12 to 17 years divided into 6 equivalent age subgroups performed maximum bilateral isometric leg press efforts. The parameters analysed were the maximal voluntary isometric force (MVC), relative strength (MVC/body mass and MVC/fat free mass), starting strength (F50: force exerted during the first 50 ms of the contraction) and speed strength index (the ratio of maximal force to time to attain maximal force).

RESULTS

The results indicated that in almost all absolute force parameters, the 12-and 13-year olds demonstrated significantly (p<0.05) lower values compared with the 15(-1)6-and 17-years old groups. Age differences were also significant (p<0.05) when the effects of sexual maturation were taken into consideration in the statistical analysis but they were reduced when strength was adjusted for body mass. Finally, no significant differences for strength per unit of fat free mass were found (p>0.05).

CONCLUSIONS

Maximum absolute strength of basketball players is significantly increased from 12 to 17 years and as sexual maturation stage increases. It also appears that body mass and fat free mass should be taken into consideration when examining age effects on strength in basketball players.

Isokinetic peak torque and hamstring/quadriceps ratios in young basketball players. Effects of age, velocity, and contraction mode

AIM

The purpose of this study was to provide an extensive isokinetic profile, including peak torque and "functional" and "conventional" muscle group ratios, of basketball players throughout the developmental years 12-17. Furthermore, we investigated the effects of age and angular velocity on peak torque and reciprocal muscle group ratios, and observed the force-velocity pattern.

METHODS

Basketball players (n=180) 12 to 17 years. were divided according to their age in 6 equal (n=30) groups aged 12, 13, 14, 15, 16, 17 years. All subjects performed maximum knee extension and flexion efforts at 60 inverted exclamation mark /s and 180 inverted exclamation mark /s angular velocities under eccentric and concentric conditions. The absolute (Nm) peak torque was measured, and the relative peak torque (PT/BW) and "functional" and "conventional" reciprocal muscle group ratio (%) were calculated.

RESULTS

PT/BW values of knee flexors ranged from 0.98 to 2.29 Nm/kg and of extensors from 1.53 to 3.69 Nm/kg, across all age, velocity, and muscle action levels. PT/BW was higher at slow speed and during eccentric contraction irrespective of age and angular velocity/muscle action. The results indicated a significant (p<0.05) age-related increase in peak torque independent of changes in BW. The force-velocity patterns were similar across ages. The "functional" and "conventional" ratios were not affected by age, but increased with increase in angular velocity, except the CON(KF)/ECC(KE) ratio that was higher (p<0.05) at slow speed.

CONCLUSION

The present study provides an extensive isokinetic profile of a knee joint in basketball players throughout developmental years 12-17. Coaches and physical therapist may use these information when evaluating and planning exercise programs during training and rehabilitation.