Bilateral and gender differences during single-legged vertical jump performance in healthy teenagers

The determination of physiologic lower limb functional imbalance among healthy teenagers is important to follow the rehabilitation progress and return to normal activity of injured subjects. We investigated the differences in vertical jump capacity between both legs in a group of healthy boys and girls, considering the performances in the dominant vs. non-dominant, and in the most vs. least efficient leg. Strength and power performances were compared in 117 boys and 106 girls aged 10-16 years during a single-leg vertical countermovement jump (SLVCJ) test. When leg dominance was defined subjectively by the participant, no difference was noted between the 2 legs. Statistically significant differences were recorded between the most and less efficient leg in strength and power performances for both genders. Girls had significantly greater peak strength than did age-matched boys, but boys showed significant increases in maximal power outputs compared with that shown by age-matched girls. When the results were analyzed according to the percentage of participants falling within certain bands of limb asymmetry, approximately 20-30% showed a difference of >15% between the 2 limbs without any relation to gender. Subjective expression of leg dominance cannot be used as a predictor of SLVCJ performance. Differences of <15% in SLVCJ performance between both legs should be considered as the physiological norm in this age group. A greater appreciation of the potential diagnostic value of the SLVCJ test may be obtained if the results are interpreted in terms of the percentage of subjects falling within certain bands of limb asymmetry. Gender-based differences in the SLVCJ test vary and depend upon whether the results are interpreted in terms of strength or power output.     

Relationship between countermovement jump performance and multijoint isometric and dynamic tests of strength

The purpose of this investigation was to determine the relationship between countermovement vertical jump (CMJ) performance and various methods used to assess isometric and dynamic multijoint strength. Twelve NCAA Division I-AA male football and track and field athletes (age, 19.83 +/- 1.40 years; height, 179.10 +/- 4.56 cm; mass, 90.08 +/- 14.81 kg; percentage of body fat, 11.85 +/- 5.47%) participated in 2 testing sessions. The first session involved 1 repetition maximum (1RM) (kg) testing in the squat and power clean. During the second session, peak force (N), relative peak force (N x kg(-1)), peak power (W), relative peak power (W x kg(-1)), peak velocity (m x s(-1)), and jump height (meters) in a CMJ, and peak force and rate of force development (RFD) (N x s(-1)) in a maximal isometric squat (ISO squat) and maximal isometric mid-thigh pull (ISO mid-thigh) were assessed. Significant correlations (P < or = 0.05) were found when comparing relative 1RMs (1RM/body mass), in both the squat and power clean, to relative CMJ peak power, CMJ peak velocity, and CMJ height. No significant correlations existed between the 4 measures of absolute strength, which did not account for body mass (squat 1RM, power clean 1RM, ISO squat peak force, and ISO mid-thigh peak force) when compared to CMJ peak velocity and CMJ height. In conclusion, multijoint dynamic tests of strength (squat 1RM and power clean 1RM), expressed relative to body mass, are most closely correlated with CMJ performance. These results suggest that increasing maximal strength relative to body mass can improve performance in explosive lower body movements. The squat and power clean, used in a concurrent strength and power training program, are recommended for optimizing lower body power.     

Effects of complex training on explosive strength in adolescent male basketball players

The purpose of this study was to evaluate the effects of a complex training program, a combined practice of weight training and plyometrics, on explosive strength development of young basketball players. Twenty-five young male athletes, aged 14-15 years old, were assessed using squat jump (SJ), countermovement jump (CMJ), Abalakov test (ABA), depth jump (DJ), mechanical power (MP), and medicine ball throw (MBT), before and after a 10-week in-season training program. Both the control group (CG; n = 10) and the experimental group (EG; n = 15) kept up their regular sports practice; additionally, the EG performed 2 sessions per week of a complex training program. The EG significantly improved in the SJ, CMJ, ABA, and MBT values (p < 0.05). The CG significantly decreased the values (p < 0.05) of CMJ, ABA, and MP, while significantly increasing the MBT values (p < 0.05). Our results support the use of complex training to improve the upper and lower body explosivity levels in young basketball players. In conclusion, this study showed that more strength conditioning is needed during the sport practice season. Furthermore, we also conclude that complex training is a useful working tool for coaches, innovative in this strength-training domain, equally contributing to a better time-efficient training.     

Muscular strength and jumping performance relationships in young women athletes

The relationships between muscular strength and vertical jumping performance were examined in young women (14-19 years) track and field jumpers (n = 20) and volleyball players (n = 21). The knee extensor muscular strength measured at 9 knee angles was correlated with jumping height and peak power at the squat (SJ) and the countermovement (CMJ) vertical jump tests. Pearson product coefficient of correlation was used to test the significance of these relationships (p 0.80). Specifically, in the volleyball players, the strong relationships were noted for muscular strength at the knee angle range of 40 degrees to 90 degrees and CMJ jumping height as well as SJ peak power. Results indicate the dissimilarity in the relationships between the knee extensor muscular strength and jumping performance in the young female track and field jumpers and volleyball players. In addition, it appears that the measure selected to evaluate jumping performance alters the correlational results.     

Comparing the performance-enhancing effects of squats on a vibration platform with conventional squats in recreationally resistance-trained men

The purpose of this investigation was to compare the performance-enhancing effects of squats on a vibration platform with conventional squats in recreationally resistance-trained men. The subjects were 14 recreationally resistance-trained men (age, 21-40 years) and the intervention period consisted of 5 weeks. After the initial testing, subjects were randomly assigned to either the "squat whole body vibration" (SWBV) group (n = 7), which performed squats on a vibration platform on a Smith Machine, or the "squat"(S) group (n = 7), which performed conventional squats with no vibrations on a Smith Machine. Testing was performed at the beginning and the end of the study and consisted of 1 repetition maximum (1RM) in squat and maximum jump height in countermovement jump (CMJ). A modified daily undulating periodization program was used during the intervention period in both groups. Both groups trained at the same percentage of 1RM in squats (6-10RM). After the intervention, CMJ performance increased significantly only in the SWBV (p < 0.01), but there was no significant difference between groups in relative jump height increase (p = 0.088). Both groups showed significant increases in 1RM performance in squats (p < 0.01). Although there was a trend toward a greater relative strength increase in the SWBV group, it did not reach a significant level. In conclusion, the preliminary results of this study point toward a tendency of superiority of squats performed on a vibration platform compared with squats without vibrations regarding maximal strength and explosive power as long as the external load is similar in recreationally resistance-trained men.     

Contributing factors to performance of a medicine ball explosive power test: a comparison between jump and nonjump athletes

The present study examined the factors contributing to performance of a backward overhead medicine ball throw (B-MBT) across 2 types of athletes. Twenty male volleyball players (jump athletes) and 20 wrestlers (nonjump athletes) were evaluated on 4 measures of power, including B-MBT, chest medicine ball throw (C-MBT), countermovement vertical jump (CMJ), and power index (PI). The athletes also completed 3 measures of strength: a 1-repetition-maximum (1RM) bench press (BP), a 1RM leg press (LP), and combined BP + LP strength. Jump athletes demonstrated greater absolute scores for CMJ, C-MBT, and B-MBT (p < 0.05), whereas nonjump athletes demonstrated greater strength scores for BP and for BP + LP (p < 0.05). When performances were examined on a relative basis, jump athletes achieved superior scores for C-MBT (p < 0.05), whereas nonjump athletes had greater scores for BP, LP, and BP + LP (p < 0.05). For both groups, B-MBT had strong correlations with PI (r = 0.817 [jump] and 0.917 [nonjump]), whereas for C-MBT, only nonjump athletes demonstrated a strong correlation (r = 0.842). When expressed in relative terms, B-MBT was strongly correlated with C-MBT (r = 0.762 [jump] and 0.835 [nonjump]) and CMJ (r = 0.899 [jump] and 0.945 [nonjump]). Only nonjump athletes demonstrated strong correlations with strength for absolute LP (r = 0.801) and BP + LP (r = 0.810) strength. The interaction of upper- and lower-body strength and power in the performance of a B-MBT appears complex, with the contributing factors differing for athletes with divergent skill sets and performance demands.     

The effects of resistance training on explosive strength indicators in adolescent basketball players

ABSTRACT: Santos, EJAM and Janeira, MAAS. The effects of resistance training on explosive strength indicators in adolescent basketball players. J Strength Cond Res 26(10): 2641-2647, 2012-The purpose of this study was to assess the effects of a lower- and upper-body 10-week in-season resistance training program on explosive strength development in young basketball players. Twenty-five adolescent male athletes, aged 14-15 years old, were randomly assigned to an experimental group (EG; n = 15) and a control group (CG; n = 10). The subjects were assessed at baseline and after training for squat jump (SJ), countermovement jump (CMJ), Abalakov test, drop jump, and seated medicine ball throw (MBT). The EG showed significant increases (p < 0.05) in all the variable scores. Conversely, the CG significantly decreased (p < 0.05) in SJ, CMJ, and Abalakov test scores and significantly increased in the results of MBT test (p < 0.05). The groups were similar on pretest, but significant differences (p < 0.05) occurred on posttest in all the variables. The results of this study show that a 10-week in-season resistance training program with moderate volume and intensity loads increased vertical jump and MBT performance in adolescent male basketball players. Coaches should know that such a short resistance training program specifically designed for young basketball players induce increased explosivity levels, which are essential to a better basketball performance, with no extra overload on adolescents' skeletal muscle development.     

Acute effects of whole-body vibration on muscle activity, strength, and power

The purpose of this study was to investigate the effects of a single bout of whole-body vibration on isometric squat (IS) and countermovement jump (CMJ) performance. Nine moderately resistance-trained men were tested for peak force (PF) during the IS and jump height (JH) and peak power (PP) during the CMJ. Average integrated electromyography (IEMG) was measured from the vastus medialis, vastus lateralis, and biceps femoris muscles. Subjects performed the 2 treatment conditions, vibration or sham, in a randomized order. Subjects were tested for baseline performance variables in both the IS and CMJ, and were exposed to either a 30-second bout of whole-body vibration or sham intervention. Subjects were tested immediately following the vibration or sham treatment, as well as 5, 15, and 30 minutes posttreatment. Whole-body vibration resulted in a significantly higher (p < or = 0.05) JH during the CMJ immediately following vibration, as compared with the sham condition. No significant differences were observed in CMJ PP; PF during IS or IEMG of the vastus medialis, vastus lateralis, or biceps femoris during the CMJ; or IS between vibration and sham treatments. Whole-body vibration may be a potential warm-up procedure for increasing vertical JH. Future research is warranted addressing the influence of various protocols of whole-body vibration (i.e., duration, amplitude, frequency) on athletic performance.     

Effects of speed, agility, quickness training method on power performance in elite soccer players

The purpose of this study was to evaluate the effects of the speed, agility, quickness (SAQ) training method on power performance in soccer players. Soccer players were assigned randomly to 2 groups: experimental group (EG; n = 50) and control group (n = 50). Power performance was assessed by a test of quickness--the 5-m sprint, a test of acceleration--the 10-m sprint, tests of maximal speed--the 20- and the 30-m sprint along with Bosco jump tests--squat jump, countermovement jump (CMJ), maximal CMJ, and continuous jumps performed with legs extended. The initial testing procedure took place at the beginning of the in-season period. The 8-week specific SAQ training program was implemented after which final testing took place. The results of the 2-way analysis of variance indicated that the EG improved significantly (p < 0.05) in 5-m (1.43 vs. 1.39 seconds) and in 10-m (2.15 vs. 2.07 seconds) sprints, and they also improved their jumping performance in countermovement (44.04 vs. 4.48 cm) and continuous jumps (41.08 vs. 41.39 cm) performed with legs extended (p < 0.05). The SAQ training program appears to be an effective way of improving some segments of power performance in young soccer players during the in-season period. Soccer coaches could use this information in the process of planning in-season training. Without proper planning of the SAQ training, soccer players will most likely be confronted with decrease in power performance during in-season period.     

Relationship of handgrip strength with anthropometric and body composition variables in prepubertal children

The purpose of the present study was to examine the relationship of handgrip strength with basic anthropometric variables, hand anthropometric variables, total body and hand composition, total body and hand bone mineral density (BMD) and bone mineral content (BMC) in prepubertal children aged between 8 and 11 years (n=64, 27 boys, 37 girls). Height and body mass were measured and body mass index (BMI kg/m²) was calculated. Biceps and triceps skinfolds, arm relaxed, arm flexed, forearm and wrist girths, acromiale-radiale, radiale-stylion-radiale and midstylion-dactylion length and humerus breadth were measured. Specific hand anthropometric variables according to Visnapuu and Jürimäe [2007. Handgrip strength and hand dimensions in young handball and basketball players. J. Strength Cond. Res. 21, 923-929] were used. Five fingers’ spans, fingers’ lengths and perimeters of the hand were measured. Total body and right-hand fat percentage, fat mass and lean mass (LBM) were measured by dual-energy X-ray absorptiometry (DXA). Right-hand BMC and BMD were analysed from the bone variables. Maximal handgrip strength of the right hand was measured with the hand dynamometer. Stepwise multiple regression analysis indicated that the most important predictive value from the basic anthropometric variables was body height, explaining 76.1% (R²×100), 40.7% and 50.6% of the handgrip strength in boys, girls and total group, respectively. Measured skinfold thicknesses and breadths were not related to handgrip strength in any group. Forearm girths significantly predicted handgrip strength in boys (30.8%), girls (43.4%) and total group (43.4%). As a rule, handgrip strength was more dependent on the anthropometric and body composition variables in boys than girls. It was concluded that body height, forearm girth, midstylion-dactylion and acromiale-radiale length and hand LBM and BMC are the most limiting factors influencing handgrip strength in prepubertal children.     

Influence of strength training background on postactivation potentiation response

The aim of this study was to evaluate the influence of the subjects' level of maximal dynamic strength and training background on postactivation potentiation (PAP). A group of 23 subjects, composed of power track-and-field athletes (PT = 8), bodybuilders (BB = 7), and physically active subjects (PA = 8), participated in the study. Maximal dynamic strength (1 repetition maximum test) was assessed in the leg press exercise for subjects' characterization. Their countermovement vertical jump (CMJ) performance was assessed before and after 2 different conditioning activity (CA) protocols (1 or 3 maximum voluntary isometric contractions [MVICs] of 5-second duration in the leg press exercise) or after control (no CA), performed on separate days. No significant differences among groups were found for CMJ height or take-off velocity after any of the CA protocols (p ≤ 0.05). However, individual analysis showed that some subjects increased performance in response to the CA, despite their previous training history. We concluded that subjects' level of maximal dynamic strength and training background have no influence on PAP manifestation. Our data suggest that coaches should individually identify the athletes that are PAP responders before introducing MVICs as part of their warm-up routines.     

Relationships between legs bone mineral density, anthropometry and jumping height in prepubertal children

The aim of this study was to determine how the legs bone mineral density (BMD) is influenced by anthropometry and vertical jumping height in prepubertal children. In total, 64 8-11-year-old schoolchildren (27 boys and 37 girls) were studied. All children were at Tanner stage 1. The subjects' height and body mass were measured and BMI calculated. The following anthropometric parameters directly connected with leg were measured: skinfolds--front thigh and medial calf girths--gluteal, thigh, mid-thigh, calf and ankle; lengths--iliospinale height, trochanterion height, trochanteriontibiale laterale, tibiale-laterale height and tibiale mediale-spyrion tibiale; and breadths--biiliocristal, foot length and biepicondylar femur. Total body and legs fat mass and fat %, lean body mass (LBM) and both legs BMD were measured by DXA. Maximal jumping height was measured on the contact mat. Stepwise multiple regression analysis indicated that body height in boys (54.6%; R2 x 100) and body mass in girls (57.3%) were the most important basic anthropometric parameters that influenced BMD in legs. From the measured skinfolds, that of the front thigh characterized legs BMD by 24.9-35.6%. From the girths, the most important parameter to characterize legs BMD was that of calf (50.0-59.1%). Tibiale laterale height was the only length parameter which was highly related with legs BMD (51.1-54.5%). Biepicondylar femur was the most important breadth parameter which characterized legs BMD (51.0-54.8%). Femur breadth and tibiale-laterale height were selected (68.7%) in boys, and tibiale-laterale height and front thigh skinfold thickness (66.0%) in girls when all measured leg anthropometric parameters were analyzed together. From the body composition parameters, the most important parameter to characterize legs BMD was legs LBM (48.9-59.5%). Jumping height did not correlate with legs BMD in any studied groups. In summary, the present study demonstrated that legs LBM together with tibiale-laterale height are the main predictors of legs BMD in prepubertal children.     

Relationship between measures of balance and strength in middle-aged adults

The purpose of this study was to investigate the relationship between variables of static and dynamic postural control as well as between isometric and dynamic muscle strength. A single-group design was used. Thirty-two middle-aged healthy adults (mean age: 56 ± 4 years) performed measurements of static (unperturbed)/dynamic (perturbed) balance and of isometric (i.e., maximal isometric torque [MIT]; rate of torque development [RTD] of the plantar flexor)/dynamic (i.e., countermovement jump [CMJ] height and power) lower extremity muscle strength. No significant associations were observed between variables of static and dynamic postural control (r = +0.128-0.341, p > 0.05) and between measures of balance and strength (r = -0.189 to +0.316, p > 0.05). Significant positive correlations were detected between variables of isometric and dynamic strength ranging from r = +0.361 to +0.501 (p < 0.05). Further, simple regression analyses revealed that a 10% increase in the mean CMJ height (3.1 cm) was associated with 44.4 N·m and 118.4 N·m·s better MIT and RTD, respectively. The nonsignificant correlations between static and dynamic balance measures and between balance and strength variables imply that static and dynamic postural control and balance and strength are independent of each other and may have to be tested and trained complementarily.     

Alpine skiing is associated with higher femoral neck bone mineral density

Objective:

To evaluate the influence of elite-level alpine skiing on athletes’ skeleton.

Methods:

Thirteen professional alpine skiers (9 males and 4 females with mean age of 22.6 years) and their age- and height matched control subjects were measured with dual energy X-ray absorptiometry (total body, lumbar spine, proximal femur, forearm) and quantitative ultrasound (hand).

Results:

After adjusting for sex, age, weight and height, between-group differences were 15% (p=0.012) for the lumbar spine, 14% (p=0.022) for the femoral neck, 10% (p=0.051) for the total hip, and 11% (p=0.001) for the total body favoring the alpine skiers. However, after controlling for total body lean mass (~muscle mass), the group-differences lost their statistical significance, the borderline 10% difference (p=0.051) in femoral neck BMD excluded.

Conclusion:

Factors contributing to the alpine skiers’ higher BMD may not only include the greater muscle mass (~stronger muscles) of these athletes but also a large number of impacts and possibly other high-frequency features in external loading generated by the high-speed skiing performance.     

Effects of 8-week in-season upper and lower limb heavy resistance training on the peak power, throwing velocity, and sprint performance of elite male handball players

The aims of this study were to test the potential of in-season heavy upper and lower limb strength training to enhance peak power output (Wpeak), vertical jump, and handball related field performance in elite male handball players who were apparently already well trained, and to assess any adverse effects on sprint velocity. Twenty-four competitors were divided randomly between a heavy resistance (HR) group (age 20 ± 0.7 years) and a control group (C; age 20 ± 0.1 years). Resistance training sessions were performed twice a week for 8 weeks. Performance was assessed before and after conditioning. Peak power (W(peak)) was determined by cycle ergometer; vertical squat jump (SJ) and countermovement jump (CMJ); video analyses assessed velocities during the first step (V(1S)), the first 5 m (V(5m)), and between 25 and 30 m (V(peak)) of a 30-m sprint. Upper limb bench press and pull-over exercises and lower limb back half squats were performed to 1-repetition maximum (1RM). Upper limb, leg, and thigh muscle volumes and mean thigh cross-sectional area (CSA) were assessed by anthropometry. W(peak) (W) for both limbs (p < 0.001), vertical jump height (p < 0.01 for both SJ and CMJ), 1RM (p < 0.001 for both upper and lower limbs) and sprint velocities (p < 0.01 for V(1S) and V(5m); p < 0.001 for V(peak)) improved in the HR group. Upper body, leg, and thigh muscle volumes and thigh CSA also increased significantly after strength training. We conclude that in-season biweekly heavy back half-squat, pull-over, and bench-press exercises can be commended to elite male handball players as improving many measures of handball-related performance without adverse effects upon speed of movement.     

Development of upper body power in junior cross-country skiers

With the advent of the ski-skating technique, upper body power has increasingly been shown to be a major factor in cross-country skiing success. The purpose of this study was to evaluate 4 commonly used training methods (weight, circuit, rollerboard, and ski-specific training) for the development of upper body power (UBP) in junior cross-country skiers. Fifty-eight adolescent cross-country skiers (Boys: n = 29, age = 16.0 +/- 1.2 y and Girls: n = 29, age = 15.5 +/- 1.5 y) were assigned to one of the UBP training methods for a 10-week training program. Fourteen cross-country runners served as controls (boys: n = 7, age = 15.8 +/- 1.7 y; girls: n = 7, age = 14.9 +/- 1.3 y). Skiers were evaluated pre- and post-training for upper body strength (UBS) using a 10 repetition maximum (RM) rollerboard test, for UBP using a double-poling ergometer and for upper body endurance (UBE) with a 3-km, arms-only, rollerski endurance time trial. Competitive race results were collected during the winters before and after training as were all training data. Only the rollerboard training group improved significantly greater than the control group (p < 0.05) in UBP and UBS. Improvements in UBP, UPS, and UBE were significantly related (r = 0.545, 0.303, and 0.407, respectively) to improvements in competitive performance. These data suggest that training using a rollerboard with 5-12RM and explosive speed is more effective in developing UBP than other common training methods for adolescent cross-country skiers. The practical importance of these data was verified by the significant relationships between improvements in UBP, UBS, and UBE related to improvements in competitive race performance.     

Relationship between the 30-second wingate test and characteristics of isometric and explosive leg strength in young subjects

The aim of this study was to investigate a possible relation between power performance of the Wingate test (WT) and isometric leg strength (ILS) and explosive leg strength (ELS) characteristics in young men and women with different physical fitness levels. A total of 166 subjects, including 98 young men and 68 young women, were included in the study. The subjects were divided into a regular exercise group and a sedentary group. The physical and body mass index characteristics of the subjects were not different, and they had not taken part in the directed jumping. When the regular exercise and sedentary groups were considered together with men, women, and total population groups, no significant correlation existed between WT anaerobic fatigue index and ILS and ELS (p > 0.05), but significant positive correlations existed among peak power, peak power per weight, mean power, mean power per weight, and WT power, which were recorded in 5-second intervals (p < 0.001). Although the 5-second WT parameters were significantly correlated with ILS and ELS for the first 15-second period, this correlation was more pronounced for the last 15 seconds for all groups (p < 0.01). As a result, this study indicated that regular physical activity has a positive significant relation on WT power, ILS, and ELS in both sedentary men and women and those engaged in regular sports activities.     

Assessment of plasma opioid peptides, beta-endorphin and met-enkephalin, at the end of an international nordic ski race

Plasma met-enkephalin, beta-endorphin, cortisol and lactic acid concentrations were measured in seventeen volunteer male subjects at rest and after a long-distance nordic ski race. Immediately after the race, mean plasma met-enkephalin did not show any significant change, but significant rises in beta-endorphin, cortisol and lactic acid were noted in all skiers. The change in beta-endorphin with exercise was significantly related to the change in cortisol (r = 0.68; p less than 0.001) and to the change in plasma lactic acid (r = 0.60; p less than 0.001). Furthermore, the experienced skiers training over 150 km X week-1 of nordic ski had significantly faster skiing times in this event and showed greater beta-endorphin, cortisol and lactic acid levels than the recreational skiers who trained for 20 km X week-1. Our results imply that the changes in plasma beta-endorphin depend on the intensity of exercise. However the significance of higher levels of skiing training or previous nordic ski experience in the release of beta-endorphin is expected and cannot be excluded.     

Relationship Between Bone Mineral Density and Body Composition According to Obesity Status in Children

ObjectiveTo analyze the relationship between body composition, metabolic parameters, and bone mineral density (BMD) according to sex and the degree of obesity in children and adolescents.MethodsA total of 236 subjects with obesity, aged 10 to 15 years (36.9% girls), were enrolled. Obesity was classified into simple (SmOb) and extreme (ExOb) forms. The BMD of the total body, less head, was measured by dual energy x-ray absorptiometry, and the BMD z-score was used to evaluate the relationship of body composition with metabolic parameters.ResultsBMD z-scores were higher in subjects with ExOb than in those with SmOb. Lean mass index (LMI), body mass index z-score, and vitamin D intake showed positive relationships, whereas percentage of body fat and serum leptin level showed negative relationships with BMD z-scores in boys. In girls, LMI and body mass index z-score showed positive relationships with BMD z-scores. In multivariable linear regressions, serum leptin level showed negative relationships with BMD z-score, only in boys. In addition, positive relationships of LMI and negative relationships of percentage of body fat with BMD z-scores were observed in subjects with SmOb. However, positive relationships of LMI with BMD z-scores were attenuated in subjects with ExOb.ConclusionHigh BMD appears to be positively associated with lean mass in children and adolescents with obesity, which might be a natural protective mechanism to withstand the excess weight. However, excessive body fat appears to be negatively associated with BMD, which might attenuate the positive relationship between lean mass and BMD in subjects with ExOb.