- Email: [email protected]
Muscle enzyme and endocrine responses of elite players to Rugby League match play
e120
Abstracts / Journal of Science and Medicine in Sport 12 (2010) e1–e232
p < 0.0001). Both groups of gymnasts had greater heightadjusted bone mass than C at all sites (Z-scores: +0.4–1.7SD, p < 0.05). However, no differences were detected between AME and C for height-adjusted TrD and bone strength at the radius and tibia 4%. In contrast, all these parameters were greater in NO-AME than C (Z-scores: +0.8–1.3, p < 0.05). In the shafts (25% and 66% sites), both groups of gymnasts had greater bone strength than C (Z-scores: +0.3–2.1SD, p = 0.01–0.07), mainly due to greater bone size. Conclusion: In the epiphyses rich in trabecular bone, greater trabecular volumetric density and bone strength were found in former gymnasts without history of menstrual dysfunction but not in those who experienced amenorrhoea. In the shafts rich in cortical bone, greater bone size and strength were found in the retired gymnasts regardless of menstrual history. History of amenorrhoea may have compromised some of the skeletal benefits associated with high-impact gymnastics training. doi:10.1016/j.jsams.2009.10.246 246 Muscle enzyme and endocrine responses of elite players to Rugby League match play C. McLellan 1,∗ , D. Lovell 2 , G. Gass 1 1 Bond
University of the Sunshine Coast
2 University
The purpose of the present study was to examine the acute and short-term muscle enzyme and endocrine responses of players to Rugby League match play. Seventeen elite rugby league players were monitored for a single game. Saliva and blood samples were collected 24 h pre match, pre and post match and at 24 h intervals for a period of 5 days post game to determine plasma creatine kinase (CK) and salivary testosterone (sTest), cortisol (sCort) and testosterone:cortisol ratio (T:C). The magnitude of change in variables at each sample collection time point compared with 24 h pre game. Cortisol and CK displayed significant (p < 0.05) pre to post match changes. CK increased significantly (p < 0.05) post match with mean peak CK measured 24 h post game (889.25 ± 238.27 U L−1 ). Cortisol displayed a clear pattern of response with significant (p < 0.05) elevations up to 24 h post-pre game, compared with 24 h pre. The hormonal and muscle enzyme profile identified a substantial acute muscle damage and catabolic state associated with the rigors of rugby league match play. A return to normal anabolic:catabolic status within 24–48 h indicates a minimum period of 48 h is required for hormonal homeostasis post competition whilst a more prolonged period of at least 5 days modified activity is required to achieve full recovery following muscle damage during match play. doi:10.1016/j.jsams.2009.10.247
247 Reliability of the ImpSFB7 bio-impedance analyser for body composition analysis R. Callister ∗ , N. Simpson, R. Dyson, A. Miller, P. Morgan, D. Lubans, C. Collins University of Newcastle Background: Bioelectrical impedance technology is an increasingly marketed method of evaluating body composition in a wide range of populations. The ImpSFB7 (ImpediMed Ltd., QLD) bio-impedance analyser (BIA) estimates fat mass (FM) and fat free mass by multi-frequency analysis of total body water (TBW) through principles of body electrical conductivity. The aim of this study was to assess the reliability of the ImpSFB7 BIA in a population varying in physical activity status. Methods: Participants (n = 24) were 14 males and 10 females aged 20–47 years and with weight stable profiles. Participants attended the laboratory on 3 occasions and were assessed for height, weight, BIA (3 visits) and 8 skinfold thicknesses (2 visits). BIA was used to determine TBW, %TBW, FM and %FM. Reliability was assessed by % inter-trial change in the mean (group changes), typical error (within subject), and intraclass correlation coefficients (ICC; rank order) using reliability analysis spreadsheets (www.sportsci.org). Results: The results are presented in the table below. Variable
TBW %TBW BIA % FM Sum of 8 skinfolds
% Change in mean T2 v T1
T3 v T2
0.6 1.3 5.2 4.0
0.3 0.1 5.7
% Typical error
ICC
1.8 1.9 8.8 2.4
0.99 0.96 0.95 0.99
Conclusion: TBW and % TBW are very reliable BIA derived measures. BIA % FM may be suitable for group analysis of body composition but has unacceptably high error for individual assessments. This appears to be a consequence of the algorithm used to calculate % FM and suggests that further development of algorithms, possibly subpopulation specific, are necessary for optimal use of this technology. doi:10.1016/j.jsams.2009.10.248
Abstracts / Journal of Science and Medicine in Sport 12 (2010) e1–e232
p < 0.0001). Both groups of gymnasts had greater heightadjusted bone mass than C at all sites (Z-scores: +0.4–1.7SD, p < 0.05). However, no differences were detected between AME and C for height-adjusted TrD and bone strength at the radius and tibia 4%. In contrast, all these parameters were greater in NO-AME than C (Z-scores: +0.8–1.3, p < 0.05). In the shafts (25% and 66% sites), both groups of gymnasts had greater bone strength than C (Z-scores: +0.3–2.1SD, p = 0.01–0.07), mainly due to greater bone size. Conclusion: In the epiphyses rich in trabecular bone, greater trabecular volumetric density and bone strength were found in former gymnasts without history of menstrual dysfunction but not in those who experienced amenorrhoea. In the shafts rich in cortical bone, greater bone size and strength were found in the retired gymnasts regardless of menstrual history. History of amenorrhoea may have compromised some of the skeletal benefits associated with high-impact gymnastics training. doi:10.1016/j.jsams.2009.10.246 246 Muscle enzyme and endocrine responses of elite players to Rugby League match play C. McLellan 1,∗ , D. Lovell 2 , G. Gass 1 1 Bond
University of the Sunshine Coast
2 University
The purpose of the present study was to examine the acute and short-term muscle enzyme and endocrine responses of players to Rugby League match play. Seventeen elite rugby league players were monitored for a single game. Saliva and blood samples were collected 24 h pre match, pre and post match and at 24 h intervals for a period of 5 days post game to determine plasma creatine kinase (CK) and salivary testosterone (sTest), cortisol (sCort) and testosterone:cortisol ratio (T:C). The magnitude of change in variables at each sample collection time point compared with 24 h pre game. Cortisol and CK displayed significant (p < 0.05) pre to post match changes. CK increased significantly (p < 0.05) post match with mean peak CK measured 24 h post game (889.25 ± 238.27 U L−1 ). Cortisol displayed a clear pattern of response with significant (p < 0.05) elevations up to 24 h post-pre game, compared with 24 h pre. The hormonal and muscle enzyme profile identified a substantial acute muscle damage and catabolic state associated with the rigors of rugby league match play. A return to normal anabolic:catabolic status within 24–48 h indicates a minimum period of 48 h is required for hormonal homeostasis post competition whilst a more prolonged period of at least 5 days modified activity is required to achieve full recovery following muscle damage during match play. doi:10.1016/j.jsams.2009.10.247
247 Reliability of the ImpSFB7 bio-impedance analyser for body composition analysis R. Callister ∗ , N. Simpson, R. Dyson, A. Miller, P. Morgan, D. Lubans, C. Collins University of Newcastle Background: Bioelectrical impedance technology is an increasingly marketed method of evaluating body composition in a wide range of populations. The ImpSFB7 (ImpediMed Ltd., QLD) bio-impedance analyser (BIA) estimates fat mass (FM) and fat free mass by multi-frequency analysis of total body water (TBW) through principles of body electrical conductivity. The aim of this study was to assess the reliability of the ImpSFB7 BIA in a population varying in physical activity status. Methods: Participants (n = 24) were 14 males and 10 females aged 20–47 years and with weight stable profiles. Participants attended the laboratory on 3 occasions and were assessed for height, weight, BIA (3 visits) and 8 skinfold thicknesses (2 visits). BIA was used to determine TBW, %TBW, FM and %FM. Reliability was assessed by % inter-trial change in the mean (group changes), typical error (within subject), and intraclass correlation coefficients (ICC; rank order) using reliability analysis spreadsheets (www.sportsci.org). Results: The results are presented in the table below. Variable
TBW %TBW BIA % FM Sum of 8 skinfolds
% Change in mean T2 v T1
T3 v T2
0.6 1.3 5.2 4.0
0.3 0.1 5.7
% Typical error
ICC
1.8 1.9 8.8 2.4
0.99 0.96 0.95 0.99
Conclusion: TBW and % TBW are very reliable BIA derived measures. BIA % FM may be suitable for group analysis of body composition but has unacceptably high error for individual assessments. This appears to be a consequence of the algorithm used to calculate % FM and suggests that further development of algorithms, possibly subpopulation specific, are necessary for optimal use of this technology. doi:10.1016/j.jsams.2009.10.248