Of the few studies examining negative consequences associated with workloads , increases in training load led to increases in injury rates , while longer training duration was associated with a greater incidence of illness .
Conclusion The combined capacity for adolescent males to grow , train and improve physical performance highlights and underscores an exciting responsiveness to training in the football environment .
However , the capacity to train has some established barriers for adolescents experiencing high workloads , which could also result in negative consequences .
Background The expectation that training enhances performance is well explored in professional sport .
However , the additional challenges of physical and cognitive maturation may require careful consideration when determining workloads to enhance performance in adolescents .
Objective The objective of this study was to determine the state of knowledge on the relationship between workloads , physical performance , injury and /or illness in adolescent male football players .
Cardiac output and stroke volume changes with endurance training: the HERITAGE Family Study.
PURPOSE The purpose of this study was to determine the magnitude of changes in cardiac output ( Qc ) , stroke volume ( SV ) , and arterial-mixed venous oxygen difference ( a-vO2 diff ) during submaximal exercise following a 20-wk endurance training program , with the primary focus on identifying differences in response by race , sex , and age . METHODS The participants in this study ( N = 631 ) were healthy and previously sedentary men ( N = 277 ) and women ( N = 354 ) of varying age ( 17 - 65 yr ) and race ( blacks , N = 217 ; whites , N = 414 ) who had completed the HERITAGE Family Study protocol . After baseline measurements , participants trained on cycle ergometers 3 d x wk(-1 ) for a total of 60 exercise sessions starting at the HR associated with 55 % of maximal oxygen uptake ( VO2max ) for 30 min/session and building to the HR associated with 75 % of VO2max for 50 min/session , which was maintained during the last 6 wk . HR , Qc ( CO2 rebreathing ) , and SV ( Qc/HR ) were determined in duplicate at 50 W and at 60 % of VO2max on two different days both before and after training . RESULTS After training , there were significant decreases in HR and Qc , and significant increases in SV and a-vO2 diff at 50 W ( except for no change in a-vO2 diff in black men ) . The changes in HR differed by sex and age , and the changes in SV , Qc , and a-vO2 diff differed by race . Qc decreased by 0.6 L x min(-1 ) at 50 W for the total sample , consistent with the decrease in VO2 at this power output . At 60 % of VO2max HR decreased , and SV , Q , and a-VO2 diff increased . There were small differences in response by sex ( HR and SV ) , race ( HR ) , and age ( HR and Qc ) . CONCLUSION It is concluded that the cardiovascular systems of men and women , blacks and whites , and younger and older subjects are not limited in their ability to adapt to endurance training
Of the few studies examining negative consequences associated with workloads , increases in training load led to increases in injury rates , while longer training duration was associated with a greater incidence of illness .
Conclusion The combined capacity for adolescent males to grow , train and improve physical performance highlights and underscores an exciting responsiveness to training in the football environment .
However , the capacity to train has some established barriers for adolescents experiencing high workloads , which could also result in negative consequences .
Background The expectation that training enhances performance is well explored in professional sport .
However , the additional challenges of physical and cognitive maturation may require careful consideration when determining workloads to enhance performance in adolescents .
Objective The objective of this study was to determine the state of knowledge on the relationship between workloads , physical performance , injury and /or illness in adolescent male football players .