physical fitness is the ability that helps people to adapt with their environmental conditions and plays an important role in daily activities .
it is highly associated to one 's health status and has a striking effect on the quality of life , learning and working efficiency , and physical activity contributions .
physical fitness is composed of performance - related physical fitness and health - related physical fitness .
indeed , genetic somehow determines physical fitness , but environmental factors including physical activity levels , socioeconomic status , television viewing , and anthropometric factors highly modify it . since fitness level drops with aging , physical involvement should be highly suggested .
however , inactive life affects body muscle and functioning ability negatively , and people are vulnerable to chronic diseases as consequences .
a higher quality of life can be obtained through moderate exercises to develop or maintain physical fitness .
lamb declared that individuals can successfully cope with challenges in their life via optimal physical fitness .
physical training program can be effective for athletes and nonathletes in different ages to improve aerobic power , muscle strength , anaerobic power , jumping ability , and local muscle endurance .
additional strength training and plyometric training in 912-year - old soccer players for 2 years showed a significant improvement of motor performance factors .
mini - trampoline exercises may need higher levels of involvement in the muscles of lower extremities .
since mini - trampoline exercises comprise a multicomponent approach , numerous physical factors including strength , body stability , muscle coordinative responses , joint movement amplitudes , and spatial integration can be affected positively .
. indicated not only balance and strength improvement but also muscular imbalances equalization of the two limbs due to mini - trampoline training .
. showed improvement in motor performance of participants with intellectual disabilities after applying trampoline training intervention .
however , rebounding exercise for 11 weeks revealed minimal cardiorespiratory fitness improvement and no significant body composition changes in 17 sedentary women .
very few studies were conducted to detect specific contributions derived from trampoline exercise as a different training model approach .
therefore , the purpose of this study was to examine the effect of trampoline training intervention on anthropometric variables and physical fitness components of 1114-year - old male students , iran .
thirty - eight healthy school - aged male students ( mean age : 12.6 years , standard deviation : 2.1 ) were selected randomly from the junior high schools of ardabil , iran .
they were divided into two groups of 19 students based on gender , residential school , and no trampoline training experience .
the first five students were omitted as they had prior experience , and the second five students were excluded because they had failed to attend the exercise sessions consistently [ figure 1 ] .
the study protocol received approval from the ethics committee of the university of urmia , and it was in accordance with the declaration of helsinki ( last modified in 2000 ) .
flow chart of the progress through the phases of the study according to the consort statements evaluation process of participants was conducted within a 2-day period by the same researcher .
the 1 day was assigned to anthropometric measurement and the 2 day for motor ability tests .
anthropometry and motor ability of the participants were measured before and after the 20 weeks trampoline training intervention .
, crymych , dyfed , uk ) and weight ( model ds-410 , seiko , tokyo , japan ) were assessed to the nearest 10 mm and 0.1 kg respectively , and body mass index was calculated using following formula : weight ( kg)/(height [ m ] ) .
moreover , lower extremity girths including thigh and calf were measured on the right side of each participant .
skinfolds thickness was measured at three body sites ( triceps , subscapula , and suprailiac ) with a harpenden skinfold caliper .
participants in experimental group trained 20-week , 1.5 h / session with 10 min rest , in 4 times trampoline training programs per week .
although none of the students had balance problems , some important safety guidelines were considered to prevent the possibility of injury .
all participants were instructed to perform variety of movements with eyes opened including one foot and two - foot jump , hop with rotation in different directions , hand and toe contacts in the air , and alternate sit and stand movement . the instructor started to teach forward and backward somersault when participants were familiar with spatial awareness , spatial orientation , and body control after performing all of the mentioned movements . finally , students were asked to combine individual movements and execute them as a routine throughout the training sessions .
however , participants in the control group only participated in school physical education classes 2 times / week for 45 min .
motor ability of all participants was assessed after a short period of warm up using standing long jump and vertical jump based on eurofit test battery .
each participant standing reach height , tip of middle finger in the hand closest to the wall while participant stood side on to the wall , was marked .
then , participant used both arms and legs contributions to project the body as high as possible while standing away from the wall . the standing reach height and the jump height difference were the score .
each participant stood behind the marked line on the ground with swinging arms and bending knees .
the take - off was done when the arms reached forward to lead participant as far as possible .
a two - way repeated measures analysis of variance ( anova ) ( condition    trial ) with repeated measures on both factors was used . to further analyze the responses of the groups
thirty - eight healthy school - aged male students ( mean age : 12.6 years , standard deviation : 2.1 ) were selected randomly from the junior high schools of ardabil , iran .
they were divided into two groups of 19 students based on gender , residential school , and no trampoline training experience .
the first five students were omitted as they had prior experience , and the second five students were excluded because they had failed to attend the exercise sessions consistently [ figure 1 ] .
the study protocol received approval from the ethics committee of the university of urmia , and it was in accordance with the declaration of helsinki ( last modified in 2000 ) .
flow chart of the progress through the phases of the study according to the consort statements
the 1 day was assigned to anthropometric measurement and the 2 day for motor ability tests .
anthropometry and motor ability of the participants were measured before and after the 20 weeks trampoline training intervention .
, crymych , dyfed , uk ) and weight ( model ds-410 , seiko , tokyo , japan ) were assessed to the nearest 10 mm and 0.1 kg respectively , and body mass index was calculated using following formula : weight ( kg)/(height [ m ] ) . moreover , lower extremity girths including thigh and calf were measured on the right side of each participant .
skinfolds thickness was measured at three body sites ( triceps , subscapula , and suprailiac ) with a harpenden skinfold caliper .
participants in experimental group trained 20-week , 1.5 h / session with 10 min rest , in 4 times trampoline training programs per week .
although none of the students had balance problems , some important safety guidelines were considered to prevent the possibility of injury .
all participants were instructed to perform variety of movements with eyes opened including one foot and two - foot jump , hop with rotation in different directions , hand and toe contacts in the air , and alternate sit and stand movement . the instructor started to teach forward and backward somersault when participants were familiar with spatial awareness , spatial orientation , and body control after performing all of the mentioned movements .
finally , students were asked to combine individual movements and execute them as a routine throughout the training sessions .
however , participants in the control group only participated in school physical education classes 2 times / week for 45 min .
motor ability of all participants was assessed after a short period of warm up using standing long jump and vertical jump based on eurofit test battery .
each participant standing reach height , tip of middle finger in the hand closest to the wall while participant stood side on to the wall , was marked .
then , participant used both arms and legs contributions to project the body as high as possible while standing away from the wall . the standing reach height and the jump height difference were the score .
each participant stood behind the marked line on the ground with swinging arms and bending knees .
the take - off was done when the arms reached forward to lead participant as far as possible .
. a two - way repeated measures analysis of variance ( anova ) ( condition    trial ) with repeated measures on both factors was used . to further analyze the responses of the groups
anthropometric and physical fitness variables of the two groups are reported in tables 1 and 2 .
the anova repeated measurement test showed a statistically significant main effect of time in calf girth p = 0.001 , fat% p = 0.01 , vertical jump p = 0.001 , and long jump p = 0.001 .
the anova repeated measurement test revealed a statistically significant main effect of group in fat% p = 0.001 .
characteristics of the study participants differences between pre- and post - training of anthropometric and physical fitness indicators in the trampoline and control groups post hoc paired t - tests indicated statistical significant differences in trampoline group between the two measurements about calf girth ( t = 4.35 , p = 0.001 ) , fat% ( t = 5.87 , p = 0.001 ) , vertical jump ( t = 5.53 , p = 0.001 ) , and long jump ( t = 10.00 , p = 0.001 ) .
post hoc paired t - tests showed statistical significant differences in control group between the two measurements concerning calf girth ( t = 5.67 , p = 0.001 ) , vertical jump ( t = 3.88 , p = 0.002 ) , and long jump ( t = 4.22 , p = 0.001 ) .
the analysis of independent t - test ( pre- to post - subtraction between two groups ) indicated significant differences in fat% p = 0.001 , high jump p = 0.02 , and long jump p = 0.02 .
this study investigated whether anthropometric measures and motor performance components are changed via trampoline training considering that this is the first study in a relatively longer period . since athletes increase metabolism through practice , our finding indicated significant changes of body fat% as a result of trampoline training that is not consistent with the findings of edin et al .
indeed , no significance changes of body composition variables in the study of edin et al ( 1990 ) may be attributed to the 11 weeks exercise that is limited in terms of training period compared to our study .
although trampoline exercises are not basically aerobic , long - term training program made significant changes in body fat% between the two groups .
lower limb characteristics such as thigh girth and calf girth were improved considering pre - test and post - test differences .
however , we found no significant difference between experimental and control group in this regard .
the improved lower limb muscle sizes are related to participant 's growth process , and trampoline training has no significant effect on the hypertrophy of lower limb muscles .
( 2011 ) reported balance improvement due to mini - trampoline exercises in elderly participants .
( 2013 ) indicated improvement in motor performance of participants with intellectual disabilities after applying trampoline training intervention .
our findings are in agreement with those studies in this regard and showed significant improvement of jumping ability in healthy trampoline participants compared to control group .
this improvement can be attributed to the higher amount of biomechanical stimuli with jumping on a trampoline compared to other forms of activity like running .
furthermore , body segments coordination due to training programs can help participants to use the ideal motor patterns for performing jumping tests .
trampoline training stimulates proprioceptive sense that can facilitate motor performance and prevent musculoskeletal injuries as a result of sudden fall in life .
since the nature of this training intervention is recreational , people in different ages can be involved to promote the quality of their life .
based on these finding , we can conclude that a 20-week trampoline training with four physical activity sessions / week in 1114-year - old students seem to have a significant effect on body fat% reduction and effective results in terms of anaerobic physical fitness .
therefore , it is suggested that different training model approach such as trampoline exercises can help students to promote the level of health and motor performance .
 background : physical exercises can influence some anthropometric and fitness components differently . 
 the aim of present study was to evaluate how a relatively long - term training program in 11 - 14-year - old male iranian students affects their anthropometric and motor performance measures.methods:measurements were conducted on the anthropometric and fitness components of participants ( n = 28 ) prior to and following the program . 
 they trained 20 weeks , 1.5 h / session with 10 min rest , in 4 times trampoline training programs per week . 
 motor performance of all participants was assessed using standing long jump and vertical jump based on eurofit test battery.results:the analysis of variance ( anova ) repeated measurement test showed a statistically significant main effect of time in calf girth p = 0.001 , fat% p = 0.01 , vertical jump p = 0.001 , and long jump p = 0.001 . 
 the anova repeated measurement test revealed a statistically significant main effect of group in fat% p = 0.001 . 
 post hoc paired t - tests indicated statistical significant differences in trampoline group between the two measurements about calf girth ( t = 4.35 , p = 0.001 ) , fat% ( t = 5.87 , p = 0.001 ) , vertical jump ( t = 5.53 , p = 0.001 ) , and long jump ( t = 10.00 , p = 0.001).conclusions : we can conclude that 20-week trampoline training with four physical activity sessions / week in 1114-year - old students seems to have a significant effect on body fat% reduction and effective results in terms of anaerobic physical fitness . 
 therefore , it is suggested that different training model approach such as trampoline exercises can help students to promote the level of health and motor performance . 