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This study examined the acute and long-term effects of two static stretching protocols of equal duration, performed either as a single stretch or multiple shorter duration repetitions on hip hyperextension range of motion (ROM) and single leg countermovement jump height (CMJ). Thirty female gymnasts were randomly assigned to stretching (SG) or control groups (CG). The SG performed two different protocols of static stretching, three times per week for 9 weeks. One leg performed repeated stretching (3 × 30 s with 30 s rest) while the other leg performed a single stretch (90 s). The CG continued regular training. ROM and CMJ were measured pre- and 2 min post-stretching on weeks 0, 3, 6, 9, and 3 weeks into detraining. CMJ height increased over time irrespective of group (main effect time, p = 0.001), with no statistical difference between groups (main effect group, p = 0.272). Three-way ANOVA showed that, CMJ height after stretching was not affected by either stretching protocol at any time point (p = 0.503 to 0.996). Both stretching protocols equally increased ROM on weeks 6 (10.9 ± 13.4%, p < 0.001, d = 0.42), and 9 (21.5 ± 13.4%, p < 0.001, d = 0.78), and this increase was maintained during detraining (17.0 ± 15.0%, p < 0.001, d = 0.68). No increase in ROM was observed in the CG (p > 0.874). Static stretching of long duration applied either as single or multiple bouts of equal duration, results in similar acute and long-term improvements in ROM. Furthermore, both stretching protocols do not acutely affect subsequent CMJ performance, and this effect is not influenced by the large increase in ROM and CMJ overtime.

The association between force–time characteristics of isometric leg press (ILP) and countermovement jump (CMJ) with vastus lateralis (VL) muscle architecture, was examined in 19 female athletes (aged 23.2 ± 5.4 years). Peak force (PF), average rate of force development (ARFD) and rate of force development (RFD) at different time epochs were calculated from the force–time curve, as well as CMJ jump height and power. Significant correlations were found between ILP-PF and CMJ power (r = 0.658, p &lt, 0.01), while both variables were correlated with VL thickness and fascicle length (r = 0.471 to 0.648, p &lt, 0.05). Significant correlations were also observed between ILP-RFD epochs and VL fascicle length (r = 0.565 to 0.646, p &lt, 0.05) and between CMJ height with VL thickness (r = 0.523, p &lt, 0.05). Furthermore, positive correlations were found between ILP and CMJ in ARFD (r = 0.625, p &lt, 0.01) and RFD epochs (r = 0.464 to 0.566, p &lt, 0.05). ILP-PF and muscle thickness accounted for 52.8% (p = 0.002) of the variance in CMJ power. These results suggest that isometric force time characteristics are associated with power generation during dynamic muscle actions. Furthermore, VL muscle thickness and fascicle length are associated with rapid force production in female athletes, irrespective of the type of muscle action.

Bogdanis, GC, Donti, O, Tsolakis, C, Smilios, I, and Bishop, DJ. Intermittent but not continuous static stretching improves subsequent vertical jump performance in flexibility-trained athletes. J Strength Cond Res 33(1): 203-210, 2019-This study examined changes in countermovement jump (CMJ) height after an intermittent or a continuous static stretching protocol of equal total duration. Sixteen male, elite-level gymnasts performed 90 seconds of intermittent (3 × 30 seconds with 30 seconds rest) or continuous stretching (90 seconds) of the quadriceps muscle. A single-leg stretching and jumping design was used, with the contralateral limb serving as a control. The same individuals performed both conditions with alternate legs in a randomized, counterbalanced order. One-leg CMJ height was measured for the stretched and the control leg after warm-up, immediately after stretching, and at regular intervals for 10 minutes after stretching. Range of motion (ROM) of the hip and knee joints was measured before, after, and 10 minutes poststretching. Compared with the control leg, intermittent stretching increased CMJ height by 8.1 ± 2.0%, 4 minutes into recovery (2.2 ± 2.0 cm, 95% confidence interval [CI]: 1.0-3.4 cm, p = 0.001), whereas continuous stretching decreased CMJ height by 17.5 ± 3.3% immediately after (-2.9 ± 1.7 cm, 95% CI: -2.0 to -3.7 cm, p = 0.001) and by 12.0 ± 2.7% 1 minute after stretching (-2.2 ± 2.1 cm, 95% CI: -1.2 to -3.2 cm, p = 0.001). The increases in hip (2.9 and 3.6°, p = 0.001. d = 2.4) and knee joint ROM (5.1 and 6.1°, p = 0.001. d = 0.85) after the intermittent and continuous stretching protocols were not different. The opposite effects of intermittent vs. continuous stretching on subsequent CMJ performance suggests that stretching mode is an important variable when examining the acute effects of static stretching on performance in flexibility-trained athletes.

Objective Eating disorders are associated with perfectionism in adults, but evidence is lacking in adolescent competitive athletes. This study examined eating disorder symptoms and perfectionism in a sample of 13–15 years old, adolescent rhythmic gymnasts. Methods Eighty-nine female rhythmic gymnasts (41 international and 48 recreational level gymnasts), completed the Eating Attitudes Tests 26 (EAT-26), the Sport Perfectionism Questionnaire (SPQ), the Social Desirability Scale (SDS) and provided information on their training. Results It was found that 41.46% of the international and 14.58% of the recreational level gymnasts scored ≥20 in EAT-26. International level gymnasts also scored higher than recreational in EAT-26 (p = 0.002), and its subscales Dieting (p = 0.012) and Oral Control (p ˂ 0.001) and in the Sport Perfectionism Questionnaire (p = 0.005) and the subscales Striving for Perfectionism (p ˂ 0.001) and Personal Standards (p ˂ 0.001). No differences were found between groups in the subscales Concerns over Mistakes (p = 0.429), and Negative Reactions to Imperfection (p = 0.096). Multiple regression analysis in international level gymnasts, showed that Negative Reactions to Imperfection, body mass index and training experience accounted for 33.2% of the variance in EAT-26 (adjusted R2 = 0.332, F = 6.786, p ˂ 0.001). A negative association was observed between training experience and eating disorder symptoms in international level athletes. No association was found between the subscales of perfectionism and EAT-26 in recreational gymnasts (p ˃ 0.316). Conclusions International level, adolescent rhythmic gymnasts show more eating pathology than recreational. Negative Reactions to Imperfection and BMI seem relevant for gymnasts' dieting behaviour while training experience may help adolescent athletes to cope with disturbed eating behaviours.

This study examined heart rate (HR) responses during a sport-specific high-intensity circuit training session to indirectly assess cardiorespiratory stress in child athletes. Seventeen, female gymnasts, aged 9&ndash, 11 years performed two 5-min 15 s sets of circuit exercise, interspersed by a 3 min rest interval. Each set included five rounds of five gymnastic exercises (7 s work, 7 s rest) executed with maximal effort. During the first circuit training set, peak heart rate (HR) was 192 &plusmn, 7 bpm and average HR was 83 &plusmn, 4% of maximum HR (HRmax), which was determined in a separate session. In the second set, peak HR and average HR were increased to 196 &plusmn, 8 bpm (p &lt, 0.001, d = 0.55) and to 89 &plusmn, 4% HRmax (p &lt, 0.001, d = 2.19), respectively, compared with the first set. HR was above 80% HRmax for 4.1 &plusmn, 1.2 min during set 1 and this was increased to 5.1 &plusmn, 0.4 min in set 2 (p &lt, 0.001, d = 1.15). Likewise, HR was above 90% of HRmax for 2.0 &plusmn, 1.2 min in set 1 and was increased to 3.4 &plusmn, 1.7 min in set 2 (p &lt, 0.001, d = 0.98). In summary, two 5-min 15 s sets of high-intensity circuit training using sport-specific exercises, increased HR to levels above 80% and 90% HRmax for extended time periods, and thus may be considered as an appropriate stimulus, in terms of intensity, for improving aerobic fitness in child female gymnasts.

&Tau, his study examined changes in hip joint flexion angle after an intermittent or a continuous static stretching protocol of equal total duration. Twenty-seven female subjects aged 19.9 &plusmn, 3.0 years (14 artistic and rhythmic gymnasts and 13 team sports athletes), performed 3 min of intermittent (6 &times, 30 s with 30 s rest) or continuous static stretching (3 min) of the hip extensors, with an intensity of 80&ndash, 90 on a 100-point visual analogue scale. The order of stretching was randomized and counterbalanced, and each subject performed both conditions. Hip flexion angle was measured with the straight leg raise test for both legs after warm-up and immediately after stretching. Both stretching types equally increased hip flexion angle by ~6% (continuous: 140.9&deg, &plusmn, 20.4&deg, to 148.6&deg, 18.8&deg, p = 0.047, intermittent: 141.8&deg, 20.3&deg, to 150.0&deg, p = 0.029) in artistic and rhythmic gymnasts. In contrast, in team sports athletes, only intermittent stretching increased hip flexion angle by 13% (from 91.0&deg, 7.2&deg, to 102.4&deg, 14.5&deg, p = 0.001), while continuous stretching did not affect hip angle (from 92.4&deg, 6.9&deg, vs. 93.1&deg, 9.2&deg, p = 0.99). The different effect of intermittent vs. continuous stretching on hip flexion between gymnasts and team sports athletes suggests that responses to static stretching are dependent on stretching mode and participants training experience.

Gastrocnemius medialis (GM) architecture and ankle angle were compared between flexibility trained (n = 10) and not trained (n = 6) female athletes, aged 8&ndash, 10 years. Ankle angle, fascicle length, pennation angle and muscle thickness were measured at the mid-belly and the distal part of GM, at rest and at the end of one min of static stretching. Flexibility trained (FT) and not trained athletes (FNT) had similar fascicle length at the medial (4.19 &plusmn, 0.37 vs. 4.24 &plusmn, 0.54 cm, respectively, p = 0.841) and the distal part of GM (4.25 &plusmn, 0.35 vs. 4.18 &plusmn, 0.65 cm, respectively, p = 0.780), similar pennation angles, and muscle thickness (p &gt, 0.216), and larger ankle angle at rest (120.9 &plusmn, 4.2 vs. 110.9 &plusmn, 5.8&deg, respectively, p = 0.001). During stretching, FT displayed greater fascicle elongation compared to FNT at the medial (+1.67 &plusmn, 0.37 vs. +1.28 &plusmn, 0.22 cm, respectively, p = 0.048) and the distal part (+1.84 &plusmn, 0.67 vs. +0.97 &plusmn, 0.97 cm, respectively, p = 0.013), larger change in joint angle and muscle tendon junction displacement (MTJ) (p &lt, 0.001). Muscle thickness was similar in both groups (p &gt, 0.053). Ankle dorsiflexion angle significantly correlated with fascicle elongation at the distal part of GM (r = &minus, 0.638, p &lt, 0.01) and MTJ displacement (r = &minus, 0.610, p &lt, 0.05). Collectively, FT had greater fascicle elongation at the medial and distal part of GM and greater MTJ displacement during stretching than FNT of similar age.

Aim: It is well documented that static stretching acutely increases range of motion (ROM) in a dose-dependent manner. However, most previous studies have utilized intermittent stretching protocols, and it is not known if intermittent and continuous stretches elicit different changes in joint ROM and, in particular, in flexibility-trained subjects. The aim of this study was to examine changes in hip joint ROM after an intermittent or a continuous static stretching protocol of equal total duration. Material & Method: Twenty-seven female subjects (age, 19.9 ± 3.0 years; height, 167.3 ± 6.1 cm; body mass, 58.2 ± 5.2 kg), 14 artistic and rhythmic gymnasts, and 13 recreationally active participants performed 3 min of intermittent (6 × 30 s with 30 s rest) or continuous stretching (3 min) of the hamstring muscles, with an intensity of 8–9 on a 10-point visual analogue scale. Hip joint ROM was measured for both legs after warm-up and immediately after stretching. The same individuals performed both conditions with alternate legs in a randomized, counterbalanced order. Data were analysed using mixed-model three-way ANOVA. Results: In the untrained participants, only intermittent stretching increased ROM by 13% (from 91.0 ± 7.2° to 102.4 ± 14.5°, p = 0.001), while continuous stretching did not affect ROM (from 92.4 ± 6.9° to 93.1 ± 9.2°, p = 0.99). In the trained participants, both stretching types equally increased ROM by ~6% (continuous, 140.9 ± 20.4° to 148.6 ± 18.8°, p = 0.047; intermittent, 141.8 ± 20.3° to 150.0 ± 18.8°, p = 0.029). Conclusions: The different effect of intermittent vs. continuous stretching on hip ROM between trained and untrained subjects suggests that stretching mode is an important variable when examining the acute effects of static stretching on ROM enhancement.

AIM: Ballet dancers’ performance is based on the execution of complex technical skills that require an unusually large range of motion (ROM) and increased muscular power. Static stretching is commonly used to increase ROM, but it may induce a transient decrease in muscle power. However, this may depend on the population and stretching protocol. The purpose of this study was to compare the acute effect of a short (20 s) vs. a long (60 s) static stretching protocol on joint ROM and jumping performance in ballet dancers. MATERIAL & METHOD: Sixteen female professional ballet dancers (age, 25.9 ± 2.7; dancing experience, 19.6 ± 3.8 y) performed 5 days of testing using a single-leg stretching and jumping design. Baseline measurements of one-leg countermovement jump (CMJ) and a ballet technical jump with one leg (“temps levé”, TL) were performed on the first visit. On the other four visits, dancers stretched their hamstrings, quadriceps and plantar flexors for 20 or 60 s per muscle group and then performed a CMJ or a TL in a counterbalanced order. This combination of stretching and jumping resulted in four conditions: long stretch-CMJ, long stretch-TL, short stretch-CMJ and short stretch-TL. In all conditions, ankle joint ROM was measured at rest and immediately after stretching. RESULTS: ROM significantly increased following stretching (p = 0.01) with no difference between stretching protocols (p = 0.505). CMJ height decreased post-stretching following both stretching protocols (p = 0.01); however, the long-duration static stretching induced a larger decrease in jump height (p = 0.020). TL height remained unchanged after the short and the long stretching protocols (7.7 ± 2.1 to 7.4 ± 2.2 vs. 7.7 ± 2.1 to 7.2 ± 2.0 cm, respectively, p = 0.701). CONCLUSION: Both stretching protocols similarly increased ankle joint ROM and decreased one-leg CMJ height immediately post-stretching. Also, both stretching protocols did not decrease TL height, probably because dancers are able to compensate for the stretch-induced deficit in muscle power through motor coordination.

AIM: Rate of force development (RFD) of the leg extensor muscles is important for jumping performance. Static stretching has been shown to reduce explosive force generation, but little is known regarding changes in muscle architectural characteristics due to stretching and jumping performance alterations. Τhe aim of this study was to determine the effects of two different static stretching protocols (20 or 60 s) on gastrocnemius medialis (GM) muscle architectural characteristics and RFD during jumping in a population with long-term flexibility training background. MATERIAL & METHOD: Twelve female professional ballet dancers (age, 25.3 ± 2.2 years) performed 5 days of testing using a single leg stretching and jumping design. RFD during one-leg countermovement jump and jump height were measured on the first visit. On the other four visits, dancers stretched their hamstrings, quadriceps and plantar flexors for 20 or 60 s per muscle group, in a counterbalanced order. Immediately after stretching, RFD and jump height were measured. Fascicle length (FL), pennation angle (PA), and muscle thickness (MT) at the medial and the distal part of GM were assessed at rest and during static stretching for each protocol, using ultrasonography. RESULTS: There was a main effect of time for FL, PA, and MT (p < 0.01) with no difference between stretching protocols, at the medial and distal parts of GM, in FL (p = 0.373 and p = 0.651, respectively), PA (p = 0.724 and p = 0.477, respectively) and MT (p = 0.314 and p = 0.444, respectively). Greater FL elongation was observed at the medial compared to the distal part of GM (p = 0.013) during the long stretching protocol. RFD significantly decreased after the long stretching protocol (p = 0.019), while it remained unchanged in the short stretching protocol (p = 0.061). Significant correlations were found between resting FL at the medial part of GM and RFD (r = −0.645, p = 0.05) and between fascicle elongation at the medial part of GM and CMJ height (r = 0.717, p = 0.01). CONCLUSIONS: The long static stretching protocol induced non-uniform adaptations along GM length and decreased RFD, suggesting that prolonged stretching durations should be avoided immediately before activities requiring rapid force production.

AIM: Energy supply in artistic gymnastics is derived mainly through the anaerobic metabolism, due to the brief duration of the competitive routines. However, during training, gymnasts perform repetitive exercises and routines, which may require aerobic adaptations, in order to recover fast and maintain high quality of execution. To improve this aspect of fitness, coaches use high-intensity interval circuit training with sport-specific exercises. Despite the popularity of this training method, there is limited information regarding the demands placed on aerobic metabolism, especially in very young athletes. Thus, the aim of this study was to examine heart rate responses during a high-intensity functional training session in female child gymnasts, to indirectly assess the contribution of aerobic energy metabolism. MATERIAL & METHOD: Seventeen girls aged 9.8 ± 0.8 years (height, 1.38 ± 0.10 m; body mass, 33.7 ± 7.25 kg) performed two 5-min sets, each consisting of five rounds of five gymnastics exercises (5–7 s work and equal rest) executed at maximal effort. The two sets were separated by a 3-min recovery period. Prior to the main measurement, athletes performed a 20-m shuttle run test until exhaustion where maximum heart rate (HRmax) was measured and the maximum oxygen uptake (VO2max) was estimated. Heart rate was continuously monitored during all sessions using a Polar team 2 system. RESULTS: VO2max was 47.8 ± 3.0 mL kg-1 min-1 and HRmax was 207 ± 5 bpm. During the first set, peak HR was 192 ± 7 bpm and average HR was 171 ± 8 bpm (83% HRmax). During the second set, peak HR was 196 ± 8 bpm and average HR was increased to 186 ± 6 bpm (90% HRmax, p < 0.001 compared with set 1). The time during which HR was above 90% of HRmax was 2.0 ± 1.2min in set 1 and increased to 3.4 ± 1.7 min in set 2 (p < 0.01). HR recovery was similar after both sets, with HR decreasing by about 30% (to 139 ± 7 bpm and 134 ± 10 bpm) after 2 min (p < 0.001). CONCLUSION: These results suggest that high-intensity training using sport-specific exercises increases HR to levels above 90% HRmax for extended time periods. Thus, this type of training may be an appropriate stimulus for concurrent improvements in muscle strength/power and aerobic fitness.

AIM: Τhe mechanisms underpinning long-term changes in muscle architectural characteristics and joint range of motion (ROM) following static stretching in humans remain under question, and data are sparse for growing athletes. It is possible that the characteristics of the stretching protocols used in previous training studies were not adequate to induce significant changes. An alternative approach would be to compare populations with different chronic flexibility training backgrounds. Thus, the purpose of this study was to examine differences in gastrocnemius medialis (GM) architectural characteristics at rest and during 1 min of static stretching between child athletes with different flexibility training backgrounds. MATERIAL & METHOD: Ten female rhythmic gymnasts (RG; age. 9.0 ± 0.7 years) were compared to six volleyball athletes (VA; age, 9.0 ± 0.6 years). Fascicle length, pennation angle and muscle thickness at the medial and distal part of GM, and ankle ROM were measured at rest and during 1 min of static stretching using ultrasonography. Data were analysed using two-way ANOVA for repeated measures on two factors (time x sport). RESULTS: At rest, RG displayed similar fascicle length compared to VA at the medial (4.19 ± 0.37 vs. 4.24 ± 0.54 cm, respectively, p = 0.841) and the distal part of GM (4.25 ± 0.35 vs. 4.18 ± 0.65 cm, respectively, p = 0.780). Pennation angle and muscle thickness were also similar in the two groups at the medial (p = 0.519 and p = 0.216, respectively) and the distal part of the gastrocnemius (p = 0.998 and p = 0.433, respectively). Ankle angle before stretching was greater in RG compared with VA (120.9 ± 4.2 vs. 110.9 ± 5.8°, respectively, p = 0.001). During the 1 min of static stretching, RG displayed greater fascicle elongation compared to the VA at the medial (5.86 ± 0.29 vs 5.52 ± 0.53 cm, p = 0.048) and the distal part (6.09 ± 0.49 vs 5.15 ± 0.65 cm, p = 0.013), as well as greater maximal ankle dorsiflexion (p < 0.001) and muscle tendon junction displacement (p < 0.001). No differences were found between groups in pennation angle (p > 0.458) and muscle thickness (p ˃ 0.237). CONCLUSIONS: Muscle architectural properties are similar at rest in child athletes with different flexibility backgrounds. However, muscle fascicle elongation is greater in rhythmic gymnasts compared to volleyball athletes and this may contribute to the greater ankle ROM observed in rhythmic gymnasts.

Background: This study examined the effects of 8 weeks of plyometric training on jumping, sprinting, and change of direction (COD) performance. Methods: Fifty female 7&ndash, 9-year-old gymnasts were randomly assigned to a plyometric training group (PG, n = 33), that performed supplementary plyometric training twice per week, and a control group (CG, n = 17) that continued regular training. The following tests were performed before and after the intervention: 10 and 20 m sprints, 5 + 5 m and 10 + 10 m COD tests, one-leg and two-leg countermovement jump (CMJ), drop jump (DJ), squat jump (SJ), and standing long jump (SLJ). Results: Only a main effect for time was found for all jumping performance parameters (p = 0.001). However, the improvement of one- and two-leg CMJ in PG had a greater effect size than CG (0.72 and 0.67 vs. 0.34 and 0.18, respectively). Group &times, time interactions were found for 10 and 20 m sprint tests (p = 0.018 and p = 0.011, respectively) and for 10 + 10 m COD (p = 0.008) with the post hoc test showing improvement only for the PG (p = 0.001, 0.001, and 0.003 and d = 1.1, 1.14, and 0.6, respectively). Conclusions: Supplementary plyometric training increased sprint and COD performance more than regular gymnastics training, while jumping performance was equally improved in both groups.

Background: This study examined gastrocnemius medialis (GM) architectural properties and ankle joint range of motion (ROM) between female athletes with different flexibility training background. Methods: Elite rhythmic gymnasts (n = 10) were compared to national level volleyball athletes (n = 10). Fascicle length, pennation angle and muscle thickness at the medial and the distal part of GM, and ankle ROM were measured at rest and during 1 min of static stretching. Results: At rest, rhythmic gymnasts displayed longer fascicles compared to volleyball athletes, at the medial (5.93 &plusmn, 0.27 vs. 4.74 &plusmn, 0.33 mm, respectively, p = 0.001) and the distal part of GM (5.63 &plusmn, 0.52 vs. 4.57 &plusmn, 0.51 mm, respectively, p = 0.001), smaller pennation angle at the medial part (22.4 &plusmn, 2.5 vs. 25.8 &plusmn, 2.4&deg, respectively, p = 0.001) and greater ankle angle (121.7 &plusmn, 4.1 vs. 113.2 &plusmn, 3.7&deg, respectively, p = 0.001). During the 1 min of static stretching, gymnasts displayed greater fascicle elongation at the distal part (p = 0.026), greater maximal ankle dorsiflexion (p &lt, 0.001) and muscle tendon junction displacement (p &lt, 0.001) with no difference between groups in pennation angles (p &gt, 0.145), muscle thickness (p &gt, 0.105), and fascicle elongation at mid-belly (p = 0.063). Conclusions: Longer muscle fascicles at rest and greater fascicle elongation at the distal part of GM may contribute to the greater ankle ROM observed in rhythmic gymnasts.

This study examined the association between physical fitness and a technical execution score in rhythmic gymnasts varying in the performance level. Forty-six young rhythmic gymnasts (age: 9.9 ±1.3 years) were divided into two groups (qualifiers, n=24 and non-qualifiers, n=22) based on the results of the National Championships. Gymnasts underwent a series of physical fitness tests and technical execution was evaluated in a routine without apparatus. There were significant differences between qualifiers and non-qualifiers in the technical execution score (p=0.01, d=1.0), shoulder flexion (p=0.01, d=0.8), straight leg raise (p=0.004, d=0.9), sideways leg extension (p=0.002, d=0.9) and body fat (p=.021, d=0.7), but no differences were found in muscular endurance and jumping performance. The technical execution score for the non-qualifiers was significantly correlated with shoulder extension (r=0.423, p

Introduction Obesity has become one of the major health risks in childhood, significantly affecting children's health and physical fitness. Although the marked increase of obesity in urban areas is well established, evidence is limited in remote and isolated areas with adverse socioeconomic features. The aim of this study was to examine the prevalence of obesity and its association with physical performance indices in young school-aged children living in 18 remote and isolated Greek islands. Methods Four hundred and sixty-three children (244 boys, 219 girls), aged 5-12 years underwent a series of physical fitness tests including 20 m sprint, standing long jump, 1 kg medicine ball throw, agility T-test and sit-and-reach test. Age and gender BMI cut-off points were determined according to World Health Organisation (WHO) norms. Results The prevalence of obesity was 23.8% and 13.2% for boys and girls, respectively. A negative body mass index (BMI) main effect was observed for weight-bearing activities, such as 20 m sprint (F=6.21, p=0.000, e2=0.041) and standing long jump (F=11.369, p=0.000, e2=0.074), while medicine ball throw was positively correlated with BMI in children aged 9-12 years. Conclusion The results of this study confirmed previous findings on obesity prevalence in Greece. A negative association was also found between BMI and physical fitness indices and, in particular, in weight-bearing activities. It is critical to establish physical education interventions and physical fitness programs at schools, aiming to increase motivation for physical activity participation.

Psychometric Properties of The Greek Version of the Test of Performance Strategies-Competition Scale (TOPS-CS) The aim of the present study was to examine the psychometric properties of the Test of Performance Strategies-Competition scale (TOPS-CS; Thomas et al., 1999) in Greek athletic population. The TOPS-CS was designed to assess eight psychological strategies used by athletes in competition (activation, automaticity, emotional control, goal-setting, imagery, negative thinking, relaxation and self-talk). In order to evaluate the psychometric properties of the inventory, two different research studies were conducted in two different age groups (n1=382 athletes, aged 16 to 20 years and n2=343 athletes, aged 12 to 15 years). Furthermore, 263 athletes, (aged 16 to 20 years) completed the TOPS-CS, purposing to perform confirmatory factor analysis. The results of the first study supported the initial factorial structure of the TOPS-CS for athletes aged 16-20 years. Reliability analysis also provided adequate evidence for the internal consistency and stability of the scale for Greek athletes of this age. However, for athletes aged 12 to 15 years, the validity and reliability of the inventory were questionable and further research is required.