Stephen-mark Cooper | Cardiff Metropolitan University (original) (raw)
Papers by Stephen-mark Cooper
Journal of Human Sport and Exercise
American Journal of Veterinary Research
Journal of Strength and Conditioning Research
American Journal of Veterinary Research
Journal of Teaching in Physical Education
The Journal of Physiology
We sought to determine the isolated and combined influence of hypovolemia and hypoxic pulmonary... more We sought to determine the isolated and combined influence of hypovolemia and hypoxic pulmonary vasoconstriction on the decrease in left ventricular (LV) function and maximal exercise capacity observed under hypobaric hypoxia. We performed echocardiography and maximal exercise tests at sea level (344m), and following 5-10 days at the Barcroft Laboratory (3800m; White Mountain, California) with and without (i) plasma volume expansion to sea level values and (ii) administration of the pulmonary vasodilator Sildenafil in a double-blinded and placebocontrolled trial. The high altitude-induced reduction in LV filling and ejection was abolished by plasma volume expansion but to a lesser extent by sildenafil administration; however, neither intervention had a positive effect on maximal exercise capacity. Both hypovolemia and hypoxic pulmonary vasoconstriction play a role in the reduction of LV filling at 3800 m, but the increase in LV filling does not influence exercise capacity at this moderate altitude.
International Journal of Performance Analysis in Sport
Abstract: The purpose of this srudy was to present a method for Assessing a reliability based upo... more Abstract: The purpose of this srudy was to present a method for Assessing a reliability based upon Bland and Altman's (1999) suggestions for the non-parametric treatment of comparison data and the proposals of Nevill et al.(2001) who recommended that 95% of ...
International Journal of Physical Education, Fitness and Sports
The purposes of this study were to a) compare a 4-min to an 8-min rest interval between composite... more The purposes of this study were to a) compare a 4-min to an 8-min rest interval between composite training (jump-sprint combination) repetitions in a single session to allow for the recovery of neuromuscular and bounce drop-jump (BDJ) performance and b) investigate if super compensation would occur after 168hrs of rest. Twelve players were randomly assigned to either a 4-min or an 8-min rest interval group. Participants first completed a BDJ test to identify individual BDJ drop heights followed by a 20m sprint test. Seventy-two hours later, a composite training session of two repetitions (three BDJs followed by a 20m sprint after a 15s rest) with either a 4-min or an 8-min rest interval was performed. A three repetition maximum (3RM) back squat strength test, a BDJ, countermovement jump (CMJ) and a sprint performance test were completed 10-mins pre- and immediately post-session, and 168 hrs post-session. CMJ force (8-min group) and BDJ (height and reactive strength index (RSI)) meas...
Purpose: To understand how training periodization influences sprint performance and key step char... more Purpose: To understand how training periodization influences sprint performance and key step characteristics over an extended training period in an elite sprint training group. Methods: Four sprinters were studied during five months of training. Step velocities, step lengths and step frequencies were measured from video of the maximum velocity phase of training sprints. Bootstrapped mean values were calculated for each athlete for each session and 139 within-athlete, between-session comparisons were made with a repeated measures ANOVA. Results: As training progressed, a link in the changes in velocity and step frequency was maintained. There were 71 between-session comparisons with a change in step velocity yielding at least a large effect size (>1.2), of which 73% had a correspondingly large change in step frequency in the same direction. Within-athlete mean session step length remained relatively constant throughout. Reductions in step velocity and frequency occurred during tra...
Journal of Strength and Conditioning Research
Experimental Physiology
What is the role of heart muscle function in the increased output of remodelled, larger hearts? W... more What is the role of heart muscle function in the increased output of remodelled, larger hearts? What is the main finding and its importance? The greater stroke volume of endurance athletes is not associated with enhanced function of the heart muscle (i.e. LV twist, torsion and twist-to-shortening) in normal and low-oxygen environments. These data indicate that, in the process of cardiac adaptation, LV twist may This article is protected by copyright. All rights reserved. 2 play an important role that is not related to generating a larger output. Since enlarged hearts with low output can develop in disease, the present findings may influence the future interpretation of heart muscle function in patients.
International journal of sports physical therapy, 2018
Due to the repetitive overhead activity involved in playing tennis and the physical demands of th... more Due to the repetitive overhead activity involved in playing tennis and the physical demands of the game, shoulder joint injury is common. There is limited research available describing sport specific risk factors for injury in tennis, however, changes in shoulder rotational range of motion (ROM) have been associated with injury in other overhead 'throwing' type sports. This study had two purposes: i) to identify reference values for passive glenohumeral joint rotational ROM in elite tennis players, and, ii) to investigate differences in ROM between various age groups of players. Cross-sectional analysis. Data was collected at national performance camps held at a National Tennis Centre between September 2012 and July 2015. One hundred and eighty-four tennis players aged between 11 and 24 years took part. All had a top eight national ranking within their respective age group. Participants were divided into three age groups; under 14 years, 14-15 years, and 16 years and over. T...
Sports medicine (Auckland, N.Z.), Mar 15, 2017
The concept of physical literacy has received increased research and international attention rece... more The concept of physical literacy has received increased research and international attention recently. Where intervention programs and empirical research are gaining momentum, their operationalizations differ significantly. The objective of this study was to inform practice in the measure/assessment of physical literacy via a systematic review of research that has assessed physical literacy (up to 14 June, 2017). Five databases were searched using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses for Protocols guidelines, with 32 published articles meeting the inclusion criteria. English-language, peer-reviewed published papers containing empirical studies of physical literacy were analyzed using inductive thematic analysis. Qualitative methods included: (1) interviews; (2) open-ended questionnaires; (3) reflective diaries; (4) focus groups; (5) participant observations; and (6) visual methods. Quantitative methods included: (1) monitoring devices (e.g., acceler...
PloS one, 2016
Increased left ventricular (LV) twist and untwisting rate (LV twist mechanics) are essential resp... more Increased left ventricular (LV) twist and untwisting rate (LV twist mechanics) are essential responses of the heart to exercise. However, previously a large variability in LV twist mechanics during exercise has been observed, which complicates the interpretation of results. This study aimed to determine some of the physiological sources of variability in LV twist mechanics during exercise. Sixteen healthy males (age: 22 ± 4 years, [Formula: see text]O2peak: 45.5 ± 6.9 ml∙kg-1∙min-1, range of individual anaerobic threshold (IAT): 32-69% of [Formula: see text]O2peak) were assessed at rest and during exercise at: i) the same relative exercise intensity, 40%peak, ii) at 2% above IAT, and, iii) at 40%peak with hypoxia (40%peak+HYP). LV volumes were not significantly different between exercise conditions (P > 0.05). However, the mean margin of error of LV twist was significantly lower (F2,47 = 2.08, P < 0.05) during 40%peak compared with IAT (3.0 vs. 4.1 degrees). Despite the same w...
International Journal of Sports Science and Coaching, 2015
Relative age effect (RAE) refers to the immediate and long-term consequences of age difference wi... more Relative age effect (RAE) refers to the immediate and long-term consequences of age difference within an age grouping. In sporting contexts, it has been widely shown that those born in the first quarter gain an advantage over those born in the last quarter of the year. Rugby union has received scant attention in relation to RAE. The primary purpose of the present study was to examine the presence and prevalence of RAE in Welsh age grade Rugby Union. A further purpose was to consider how coaches' selection processes have the potential to contribute to the manifestation of RAE. A sequential multi-method research typology was adopted to gain a richer, more contextualized understanding of RAE. Results revealed that RAE was evident in all age groups of Welsh junior club rugby from 'Under 7-19 yrs'. Odds ratios showed that the magnitude of the RAE increases with the three levels of performance (district, regional and national) above the club game. Further, the process of selection had characteristics that increased the risk of RAE occurring, especially a propensity to use physical characteristics as the primary selection criteria when selecting for representative teams. Also, coaches over emphasis on game performance and winning appeared to determine that the older, potentially bigger, faster, stronger players are preferred over the younger less physically mature players.
Research in sports medicine (Print), Jan 26, 2015
This study examined the independent relationships between cardiorespiratory and muscular fitness ... more This study examined the independent relationships between cardiorespiratory and muscular fitness with cardiometabolic risk in adolescents. Subjects were 192 adolescents (118 boys), aged 15-17.5 years. The 2 m multi-stage fitness test assessed cardiorespiratory fitness and the counter movement jump assessed muscular fitness. Additional measures included interleukin-6, C-reactive protein, adiponectin, fibrinogen and plasminogen activator inhibitor-1. Regression analysis revealed that cardiorespiratory fitness was negatively related to cardiometabolic risk (β = -0.014, p < 0.001). With additional adjustment for muscular fitness the relationship remained significant (β = -0.015, p < 0.001). Muscular fitness was negatively related to cardiometabolic risk (β = -0.021, p < 0.001) and remained significant after adjustment for cardiorespiratory fitness. Participants in the least-fit quartile for both cardiorespiratory and muscular fitness had significantly poorer cardiometabolic ris...
Pediatric exercise science, 2007
The purpose of this study was to examine relationships between aerobic fitness (AF), fatness, and... more The purpose of this study was to examine relationships between aerobic fitness (AF), fatness, and coronary-heart-disease (CHD) risk factors in 12- to 13-year-olds. The data were obtained from 208 schoolchildren (100 boys; 108 girls) ages 12.9 +/- 0.3 years. Measurements included AF, indices of obesity, blood pressure, blood lipids and lipoproteins, fibrinogen, homocysteine, and C-reactive protein. An inverse relationship was found between AF and fatness (p <or= .05). Fatness was related to a greater number of CHD risk factors than fitness was (p <or= .05). Further analysis revealed fatness to be an independent predictor of triglyceride and blood-pressure levels (p <or= .05). Our findings indicate that, for young people, fatness rather than fitness is independently related to CHD risk factors.
Scandinavian Journal of Medicine & Science in Sports, 2011
The purpose of this study was to examine the effects of exercising at different intensities over ... more The purpose of this study was to examine the effects of exercising at different intensities over 7 weeks on components of physical fitness and CVD risk factors. Forty-seven boys and 10 girls, (16.4±0.7 years of age) were divided into a moderate, high intensity, or a control group. All participants had indices of obesity and blood pressure recorded in addition to four physical performance measures pre- and post-intervention. In addition, the intervention groups repeated the physical performance measures at the 4th week phase of the intervention. Following the intervention, significant improvements (P&amp;amp;amp;amp;amp;lt;0.05) in the high-intensity group were found in the 20 MSFT, agility, CMJ and 10 m sprint post-intervention. Participants in the moderate intensity group displayed significant improvements (P&amp;amp;amp;amp;amp;lt;0.05) in both the CMJ and 20 MSFT post-intervention. Body fat % significantly improved (P&amp;amp;amp;amp;amp;lt;0.01) in the moderate group only post-intervention. Interestingly, Systolic blood pressure significantly improved post-intervention (112±10 vs 106±11 mmHg) (P=0.017) in the high intensity group. In conclusion, high-intensity exercise over 7 weeks is a very time efficient means of improving important components of physical fitness in adolescents.
Research in Sports Medicine, 2008
The aim of this unique study was to consider the relationship between folate and vitamin B(12) on... more The aim of this unique study was to consider the relationship between folate and vitamin B(12) on homocyst(e)ine (Hcy) concentration in an apparently healthy cohort of Welsh young people. A cohort of 179, 12-13 year olds (88 boys and 91 girls) were measured for Hcy, folate, vitamin B(12), adiposity, and dietary habits. Boys had significantly higher waist circumference and folate concentration than girls. Folate was negatively associated with Hcy in both sexes, whereas vitamin B(12) was negatively associated with Hcy in boys only. Adiposity was not associated with Hcy. Folate was an independent predictor of Hcy in both sexes, whilst vitamin B(12) was an independent determinant of Hcy in boys only. Familial history of cardiovascular disease (CVD) risk factors was identified in 69% of the children with elevated Hcy (&amp;gt; or = 8.5 mumol.L(-1)). Young people might be encouraged to increase their folate intake through diet, particularly by increasing their consumption of leafy vegetables and fruit. Further research is necessary to determine the exact contribution of genetics and diet on Hcy levels in young people, and whether Hcy levels during childhood and adolescence might influence future CVD risk.
Journal of Strength and Conditioning Research, 2009
The purpose of this study was to investigate whether wearing lower-body compression garments atte... more The purpose of this study was to investigate whether wearing lower-body compression garments attenuate indices of muscle damage and decrements in performance following drop-jump training. Seven trained female and four trained male subjects undertook blood collection for creatine kinase (CK) and lactate dehydrogenase (LDH), a mid-thigh girth measurement, and reported their perceived muscle soreness (PMS). A series of performance tests were then completed including sprints (5 m, 10 m, and 20 m), a 5-0-5 agility test, and a countermovement jump test. In a randomized crossover experimental design, separated by 1 week, subjects completed 5 x 20 maximal drop-jumps, followed immediately after exercise by either wearing graduated compression tights (CG) or undertook passive recovery as a control (CON) for 48 hours. CK, LDH, mid-thigh girth, and PMS were retested after 24 hours and 48 hours of recovery. The performance tests were repeated after 48 hours of recovery. Analysis of variance for repeated measures indicated that for female subjects, CK values were elevated after 24-hour recovery (p = 0.020) and a greater PMS was observed after 48-hour recovery in the CON condition (p = 0.002) but not for the CG condition. For all the subjects (n = 11), a greater PMS was observed after 48-hour recovery in the CON condition (p = 0.001) but not the CG condition. Significant increases in time were reported for 10-m (p = 0.016, 0.004) and 20-m sprints (p = 0.004, 0.001) in both the CON and CG conditions and for the 5-m sprint (p = 0.014) in the CG condition. All other parameters were unchanged in either condition. Data indicates that CK responses and PMS might be attenuated by wearing compression tights in some participants after drop-jump training; however, no benefit in performance was observed.
Journal of Human Sport and Exercise
American Journal of Veterinary Research
Journal of Strength and Conditioning Research
American Journal of Veterinary Research
Journal of Teaching in Physical Education
The Journal of Physiology
We sought to determine the isolated and combined influence of hypovolemia and hypoxic pulmonary... more We sought to determine the isolated and combined influence of hypovolemia and hypoxic pulmonary vasoconstriction on the decrease in left ventricular (LV) function and maximal exercise capacity observed under hypobaric hypoxia. We performed echocardiography and maximal exercise tests at sea level (344m), and following 5-10 days at the Barcroft Laboratory (3800m; White Mountain, California) with and without (i) plasma volume expansion to sea level values and (ii) administration of the pulmonary vasodilator Sildenafil in a double-blinded and placebocontrolled trial. The high altitude-induced reduction in LV filling and ejection was abolished by plasma volume expansion but to a lesser extent by sildenafil administration; however, neither intervention had a positive effect on maximal exercise capacity. Both hypovolemia and hypoxic pulmonary vasoconstriction play a role in the reduction of LV filling at 3800 m, but the increase in LV filling does not influence exercise capacity at this moderate altitude.
International Journal of Performance Analysis in Sport
Abstract: The purpose of this srudy was to present a method for Assessing a reliability based upo... more Abstract: The purpose of this srudy was to present a method for Assessing a reliability based upon Bland and Altman's (1999) suggestions for the non-parametric treatment of comparison data and the proposals of Nevill et al.(2001) who recommended that 95% of ...
International Journal of Physical Education, Fitness and Sports
The purposes of this study were to a) compare a 4-min to an 8-min rest interval between composite... more The purposes of this study were to a) compare a 4-min to an 8-min rest interval between composite training (jump-sprint combination) repetitions in a single session to allow for the recovery of neuromuscular and bounce drop-jump (BDJ) performance and b) investigate if super compensation would occur after 168hrs of rest. Twelve players were randomly assigned to either a 4-min or an 8-min rest interval group. Participants first completed a BDJ test to identify individual BDJ drop heights followed by a 20m sprint test. Seventy-two hours later, a composite training session of two repetitions (three BDJs followed by a 20m sprint after a 15s rest) with either a 4-min or an 8-min rest interval was performed. A three repetition maximum (3RM) back squat strength test, a BDJ, countermovement jump (CMJ) and a sprint performance test were completed 10-mins pre- and immediately post-session, and 168 hrs post-session. CMJ force (8-min group) and BDJ (height and reactive strength index (RSI)) meas...
Purpose: To understand how training periodization influences sprint performance and key step char... more Purpose: To understand how training periodization influences sprint performance and key step characteristics over an extended training period in an elite sprint training group. Methods: Four sprinters were studied during five months of training. Step velocities, step lengths and step frequencies were measured from video of the maximum velocity phase of training sprints. Bootstrapped mean values were calculated for each athlete for each session and 139 within-athlete, between-session comparisons were made with a repeated measures ANOVA. Results: As training progressed, a link in the changes in velocity and step frequency was maintained. There were 71 between-session comparisons with a change in step velocity yielding at least a large effect size (>1.2), of which 73% had a correspondingly large change in step frequency in the same direction. Within-athlete mean session step length remained relatively constant throughout. Reductions in step velocity and frequency occurred during tra...
Journal of Strength and Conditioning Research
Experimental Physiology
What is the role of heart muscle function in the increased output of remodelled, larger hearts? W... more What is the role of heart muscle function in the increased output of remodelled, larger hearts? What is the main finding and its importance? The greater stroke volume of endurance athletes is not associated with enhanced function of the heart muscle (i.e. LV twist, torsion and twist-to-shortening) in normal and low-oxygen environments. These data indicate that, in the process of cardiac adaptation, LV twist may This article is protected by copyright. All rights reserved. 2 play an important role that is not related to generating a larger output. Since enlarged hearts with low output can develop in disease, the present findings may influence the future interpretation of heart muscle function in patients.
International journal of sports physical therapy, 2018
Due to the repetitive overhead activity involved in playing tennis and the physical demands of th... more Due to the repetitive overhead activity involved in playing tennis and the physical demands of the game, shoulder joint injury is common. There is limited research available describing sport specific risk factors for injury in tennis, however, changes in shoulder rotational range of motion (ROM) have been associated with injury in other overhead 'throwing' type sports. This study had two purposes: i) to identify reference values for passive glenohumeral joint rotational ROM in elite tennis players, and, ii) to investigate differences in ROM between various age groups of players. Cross-sectional analysis. Data was collected at national performance camps held at a National Tennis Centre between September 2012 and July 2015. One hundred and eighty-four tennis players aged between 11 and 24 years took part. All had a top eight national ranking within their respective age group. Participants were divided into three age groups; under 14 years, 14-15 years, and 16 years and over. T...
Sports medicine (Auckland, N.Z.), Mar 15, 2017
The concept of physical literacy has received increased research and international attention rece... more The concept of physical literacy has received increased research and international attention recently. Where intervention programs and empirical research are gaining momentum, their operationalizations differ significantly. The objective of this study was to inform practice in the measure/assessment of physical literacy via a systematic review of research that has assessed physical literacy (up to 14 June, 2017). Five databases were searched using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses for Protocols guidelines, with 32 published articles meeting the inclusion criteria. English-language, peer-reviewed published papers containing empirical studies of physical literacy were analyzed using inductive thematic analysis. Qualitative methods included: (1) interviews; (2) open-ended questionnaires; (3) reflective diaries; (4) focus groups; (5) participant observations; and (6) visual methods. Quantitative methods included: (1) monitoring devices (e.g., acceler...
PloS one, 2016
Increased left ventricular (LV) twist and untwisting rate (LV twist mechanics) are essential resp... more Increased left ventricular (LV) twist and untwisting rate (LV twist mechanics) are essential responses of the heart to exercise. However, previously a large variability in LV twist mechanics during exercise has been observed, which complicates the interpretation of results. This study aimed to determine some of the physiological sources of variability in LV twist mechanics during exercise. Sixteen healthy males (age: 22 ± 4 years, [Formula: see text]O2peak: 45.5 ± 6.9 ml∙kg-1∙min-1, range of individual anaerobic threshold (IAT): 32-69% of [Formula: see text]O2peak) were assessed at rest and during exercise at: i) the same relative exercise intensity, 40%peak, ii) at 2% above IAT, and, iii) at 40%peak with hypoxia (40%peak+HYP). LV volumes were not significantly different between exercise conditions (P > 0.05). However, the mean margin of error of LV twist was significantly lower (F2,47 = 2.08, P < 0.05) during 40%peak compared with IAT (3.0 vs. 4.1 degrees). Despite the same w...
International Journal of Sports Science and Coaching, 2015
Relative age effect (RAE) refers to the immediate and long-term consequences of age difference wi... more Relative age effect (RAE) refers to the immediate and long-term consequences of age difference within an age grouping. In sporting contexts, it has been widely shown that those born in the first quarter gain an advantage over those born in the last quarter of the year. Rugby union has received scant attention in relation to RAE. The primary purpose of the present study was to examine the presence and prevalence of RAE in Welsh age grade Rugby Union. A further purpose was to consider how coaches' selection processes have the potential to contribute to the manifestation of RAE. A sequential multi-method research typology was adopted to gain a richer, more contextualized understanding of RAE. Results revealed that RAE was evident in all age groups of Welsh junior club rugby from 'Under 7-19 yrs'. Odds ratios showed that the magnitude of the RAE increases with the three levels of performance (district, regional and national) above the club game. Further, the process of selection had characteristics that increased the risk of RAE occurring, especially a propensity to use physical characteristics as the primary selection criteria when selecting for representative teams. Also, coaches over emphasis on game performance and winning appeared to determine that the older, potentially bigger, faster, stronger players are preferred over the younger less physically mature players.
Research in sports medicine (Print), Jan 26, 2015
This study examined the independent relationships between cardiorespiratory and muscular fitness ... more This study examined the independent relationships between cardiorespiratory and muscular fitness with cardiometabolic risk in adolescents. Subjects were 192 adolescents (118 boys), aged 15-17.5 years. The 2 m multi-stage fitness test assessed cardiorespiratory fitness and the counter movement jump assessed muscular fitness. Additional measures included interleukin-6, C-reactive protein, adiponectin, fibrinogen and plasminogen activator inhibitor-1. Regression analysis revealed that cardiorespiratory fitness was negatively related to cardiometabolic risk (β = -0.014, p < 0.001). With additional adjustment for muscular fitness the relationship remained significant (β = -0.015, p < 0.001). Muscular fitness was negatively related to cardiometabolic risk (β = -0.021, p < 0.001) and remained significant after adjustment for cardiorespiratory fitness. Participants in the least-fit quartile for both cardiorespiratory and muscular fitness had significantly poorer cardiometabolic ris...
Pediatric exercise science, 2007
The purpose of this study was to examine relationships between aerobic fitness (AF), fatness, and... more The purpose of this study was to examine relationships between aerobic fitness (AF), fatness, and coronary-heart-disease (CHD) risk factors in 12- to 13-year-olds. The data were obtained from 208 schoolchildren (100 boys; 108 girls) ages 12.9 +/- 0.3 years. Measurements included AF, indices of obesity, blood pressure, blood lipids and lipoproteins, fibrinogen, homocysteine, and C-reactive protein. An inverse relationship was found between AF and fatness (p <or= .05). Fatness was related to a greater number of CHD risk factors than fitness was (p <or= .05). Further analysis revealed fatness to be an independent predictor of triglyceride and blood-pressure levels (p <or= .05). Our findings indicate that, for young people, fatness rather than fitness is independently related to CHD risk factors.
Scandinavian Journal of Medicine & Science in Sports, 2011
The purpose of this study was to examine the effects of exercising at different intensities over ... more The purpose of this study was to examine the effects of exercising at different intensities over 7 weeks on components of physical fitness and CVD risk factors. Forty-seven boys and 10 girls, (16.4±0.7 years of age) were divided into a moderate, high intensity, or a control group. All participants had indices of obesity and blood pressure recorded in addition to four physical performance measures pre- and post-intervention. In addition, the intervention groups repeated the physical performance measures at the 4th week phase of the intervention. Following the intervention, significant improvements (P&amp;amp;amp;amp;amp;lt;0.05) in the high-intensity group were found in the 20 MSFT, agility, CMJ and 10 m sprint post-intervention. Participants in the moderate intensity group displayed significant improvements (P&amp;amp;amp;amp;amp;lt;0.05) in both the CMJ and 20 MSFT post-intervention. Body fat % significantly improved (P&amp;amp;amp;amp;amp;lt;0.01) in the moderate group only post-intervention. Interestingly, Systolic blood pressure significantly improved post-intervention (112±10 vs 106±11 mmHg) (P=0.017) in the high intensity group. In conclusion, high-intensity exercise over 7 weeks is a very time efficient means of improving important components of physical fitness in adolescents.
Research in Sports Medicine, 2008
The aim of this unique study was to consider the relationship between folate and vitamin B(12) on... more The aim of this unique study was to consider the relationship between folate and vitamin B(12) on homocyst(e)ine (Hcy) concentration in an apparently healthy cohort of Welsh young people. A cohort of 179, 12-13 year olds (88 boys and 91 girls) were measured for Hcy, folate, vitamin B(12), adiposity, and dietary habits. Boys had significantly higher waist circumference and folate concentration than girls. Folate was negatively associated with Hcy in both sexes, whereas vitamin B(12) was negatively associated with Hcy in boys only. Adiposity was not associated with Hcy. Folate was an independent predictor of Hcy in both sexes, whilst vitamin B(12) was an independent determinant of Hcy in boys only. Familial history of cardiovascular disease (CVD) risk factors was identified in 69% of the children with elevated Hcy (&amp;gt; or = 8.5 mumol.L(-1)). Young people might be encouraged to increase their folate intake through diet, particularly by increasing their consumption of leafy vegetables and fruit. Further research is necessary to determine the exact contribution of genetics and diet on Hcy levels in young people, and whether Hcy levels during childhood and adolescence might influence future CVD risk.
Journal of Strength and Conditioning Research, 2009
The purpose of this study was to investigate whether wearing lower-body compression garments atte... more The purpose of this study was to investigate whether wearing lower-body compression garments attenuate indices of muscle damage and decrements in performance following drop-jump training. Seven trained female and four trained male subjects undertook blood collection for creatine kinase (CK) and lactate dehydrogenase (LDH), a mid-thigh girth measurement, and reported their perceived muscle soreness (PMS). A series of performance tests were then completed including sprints (5 m, 10 m, and 20 m), a 5-0-5 agility test, and a countermovement jump test. In a randomized crossover experimental design, separated by 1 week, subjects completed 5 x 20 maximal drop-jumps, followed immediately after exercise by either wearing graduated compression tights (CG) or undertook passive recovery as a control (CON) for 48 hours. CK, LDH, mid-thigh girth, and PMS were retested after 24 hours and 48 hours of recovery. The performance tests were repeated after 48 hours of recovery. Analysis of variance for repeated measures indicated that for female subjects, CK values were elevated after 24-hour recovery (p = 0.020) and a greater PMS was observed after 48-hour recovery in the CON condition (p = 0.002) but not for the CG condition. For all the subjects (n = 11), a greater PMS was observed after 48-hour recovery in the CON condition (p = 0.001) but not the CG condition. Significant increases in time were reported for 10-m (p = 0.016, 0.004) and 20-m sprints (p = 0.004, 0.001) in both the CON and CG conditions and for the 5-m sprint (p = 0.014) in the CG condition. All other parameters were unchanged in either condition. Data indicates that CK responses and PMS might be attenuated by wearing compression tights in some participants after drop-jump training; however, no benefit in performance was observed.