Dalenda Zalleg - Academia.edu (original) (raw)
Papers by Dalenda Zalleg
BMC Sports Science, Medicine and Rehabilitation
Background Sex differences that appear throughout puberty have a substantial impact on the traini... more Background Sex differences that appear throughout puberty have a substantial impact on the training process. It remains unclear what effect these sex differences should have on how training programs are planned and performed and what objectives should be established for boys and girls of different ages. This study aimed to investigate the relationship between vertical jump performance and muscle volume based on age and sex. Methods One hundred eighty healthy males (n = 90) and females (n = 90) performed three different types of vertical jumps (VJ): squat jump (SJ), counter movement jump (CMJ), and counter movement jump with arms (CMJ with arms). We used the anthropometric method to measure muscle volume. Results Muscle volume differed across age groups. There were significant effects of age, sex, and their interaction on the SJ, CMJ, and CMJ with arms heights. From the age of 14–15, males exhibited better performances than females, and large effect sizes became apparent in the SJ (d...
Background A signi cant impact on the training process is caused by sex-speci c differences that ... more Background A signi cant impact on the training process is caused by sex-speci c differences that emerge throughout puberty. However, it is still unclear what impact this should have on how training programs are planned, implemented, and set goals for boys and girls of different ages. Purpose To study the relationship between vertical jump performance and muscle volume, considering age and sex factors. Methods healthy male and 90 healthy female participants (aged 9 to 22 years) performed three different types of vertical jumps: squat jump, counter movement jump without and with arm swings. A standard Anthropometric method was used to measure the muscle volume. Results Muscle volume was different across age groups. For both sexes in the Squat Jump, Counter Movement Jump, and Counter Movement Jump arms, signi cant age, sex, and interaction effects were found. From the age of 14-15, Males performed signi cantly better than females (p = 0.001). These differences persisted when performances were normalized to the length of lower limbs'. Following normalization to muscle volume males elicited better performance when compared to females. This difference persisted only for the 20-22 age group in Squat Jump (p = 0.005), Counter Movement Jump (p = 0.022) and in Counter Movement Jump with arms (p = 0.016). Signi cant correlation occurred between Muscle Volume and Squat Jump (r = 0.70; p < 0.01), Counter Movement Jump (r = 0.70; p < 0.01) and Counter Movement Jump with arms (r = 0.55; p < 0.01) for male participants. Conclusions The muscle volume appeared to be the determining factor in intersexual differences in vertical jumping performances.
BMC neurology, Jan 29, 2017
Individuals with cerebral palsy have smaller muscle volumes normalised to body mass than their ty... more Individuals with cerebral palsy have smaller muscle volumes normalised to body mass than their typically developing peers. The aim of this study is to investigate the relationship between lower limb muscle volume and body mass in young people with bilateral cerebral palsy and their typically developing peers. Twenty-five participants with bilateral cerebral palsy (aged 14.7±3.0 years, GMFCS level I-III) and 25 of their typically developing peers (aged 16.8±3.3 years) took part in this study. None of the participants had undergone orthopaedic surgery, botulinum toxin injections, or serial casting in the previous year. All participants underwent magnetic resonance imaging of both lower limbs. Nine major muscles of each lower limb were individually manually segmented and the muscle volumes calculated. Body mass and total lower limb muscle volume were significantly linearly related in both the cerebral palsy (R = 0.75, p<0.001) and typically developing (R = 0.77, p<0.001) groups. ...
Journal of sports science & medicine, 2006
Leptin, a hormone synthesized by fat tissue had been noted to regulate energy balance and metabol... more Leptin, a hormone synthesized by fat tissue had been noted to regulate energy balance and metabolism and thus to influence body weight. The influence of acute exercise and chronic exercise training on circulating leptin and its relationship with hormonal and metabolic changes that induce energy balance are presented. Research that has examined the influence of exercise under various experimental conditions on leptin and the conflicts in the literature are presented. It appears that a significant caloric perturbation (> 800 kcals) is necessary for acute exercise to result in a significant reduction in leptin. In contrast, exercise training can result in a leptin decline but typically this manifests a reduction in adipose tissue stores. In addition, future directions are presented. Key PointsPhysical exercise and training have both inhibitory and stimulatory effects on leptin.Exercise with energy expenditure higher than 800 kcal can decrease leptinemia.Acute training may cause a de...
Journal of Strength and Conditioning Research
Journal of Sports …, 2006
Parathyroid hormone (PTH) is the major hormone regulating calcium metabolism and is involved in b... more Parathyroid hormone (PTH) is the major hormone regulating calcium metabolism and is involved in both catabolic and anabolic actions on bone. Intermittent PTH exposure can stimulate bone formation and bone mass when PTH has been injected. In contrast, continuous infusion of PTH stimulates bone resorption. PTH concentration may be affected by physical exercise and our review was designed to investigate this relationship. The variation in PTH concentration appears to be influenced by both exercise duration and intensity. There probably exists a stimulation threshold of exercise to alter PTH. PTH regulation is also influenced by the initial bone mineral content, age, gender, training state, and other hormonal and metabolic factors (catecholamines, lactic acid and calcium concentrations).
BMC Sports Science, Medicine and Rehabilitation
Background Sex differences that appear throughout puberty have a substantial impact on the traini... more Background Sex differences that appear throughout puberty have a substantial impact on the training process. It remains unclear what effect these sex differences should have on how training programs are planned and performed and what objectives should be established for boys and girls of different ages. This study aimed to investigate the relationship between vertical jump performance and muscle volume based on age and sex. Methods One hundred eighty healthy males (n = 90) and females (n = 90) performed three different types of vertical jumps (VJ): squat jump (SJ), counter movement jump (CMJ), and counter movement jump with arms (CMJ with arms). We used the anthropometric method to measure muscle volume. Results Muscle volume differed across age groups. There were significant effects of age, sex, and their interaction on the SJ, CMJ, and CMJ with arms heights. From the age of 14–15, males exhibited better performances than females, and large effect sizes became apparent in the SJ (d...
Background A signi cant impact on the training process is caused by sex-speci c differences that ... more Background A signi cant impact on the training process is caused by sex-speci c differences that emerge throughout puberty. However, it is still unclear what impact this should have on how training programs are planned, implemented, and set goals for boys and girls of different ages. Purpose To study the relationship between vertical jump performance and muscle volume, considering age and sex factors. Methods healthy male and 90 healthy female participants (aged 9 to 22 years) performed three different types of vertical jumps: squat jump, counter movement jump without and with arm swings. A standard Anthropometric method was used to measure the muscle volume. Results Muscle volume was different across age groups. For both sexes in the Squat Jump, Counter Movement Jump, and Counter Movement Jump arms, signi cant age, sex, and interaction effects were found. From the age of 14-15, Males performed signi cantly better than females (p = 0.001). These differences persisted when performances were normalized to the length of lower limbs'. Following normalization to muscle volume males elicited better performance when compared to females. This difference persisted only for the 20-22 age group in Squat Jump (p = 0.005), Counter Movement Jump (p = 0.022) and in Counter Movement Jump with arms (p = 0.016). Signi cant correlation occurred between Muscle Volume and Squat Jump (r = 0.70; p < 0.01), Counter Movement Jump (r = 0.70; p < 0.01) and Counter Movement Jump with arms (r = 0.55; p < 0.01) for male participants. Conclusions The muscle volume appeared to be the determining factor in intersexual differences in vertical jumping performances.
BMC neurology, Jan 29, 2017
Individuals with cerebral palsy have smaller muscle volumes normalised to body mass than their ty... more Individuals with cerebral palsy have smaller muscle volumes normalised to body mass than their typically developing peers. The aim of this study is to investigate the relationship between lower limb muscle volume and body mass in young people with bilateral cerebral palsy and their typically developing peers. Twenty-five participants with bilateral cerebral palsy (aged 14.7±3.0 years, GMFCS level I-III) and 25 of their typically developing peers (aged 16.8±3.3 years) took part in this study. None of the participants had undergone orthopaedic surgery, botulinum toxin injections, or serial casting in the previous year. All participants underwent magnetic resonance imaging of both lower limbs. Nine major muscles of each lower limb were individually manually segmented and the muscle volumes calculated. Body mass and total lower limb muscle volume were significantly linearly related in both the cerebral palsy (R = 0.75, p<0.001) and typically developing (R = 0.77, p<0.001) groups. ...
Journal of sports science & medicine, 2006
Leptin, a hormone synthesized by fat tissue had been noted to regulate energy balance and metabol... more Leptin, a hormone synthesized by fat tissue had been noted to regulate energy balance and metabolism and thus to influence body weight. The influence of acute exercise and chronic exercise training on circulating leptin and its relationship with hormonal and metabolic changes that induce energy balance are presented. Research that has examined the influence of exercise under various experimental conditions on leptin and the conflicts in the literature are presented. It appears that a significant caloric perturbation (> 800 kcals) is necessary for acute exercise to result in a significant reduction in leptin. In contrast, exercise training can result in a leptin decline but typically this manifests a reduction in adipose tissue stores. In addition, future directions are presented. Key PointsPhysical exercise and training have both inhibitory and stimulatory effects on leptin.Exercise with energy expenditure higher than 800 kcal can decrease leptinemia.Acute training may cause a de...
Journal of Strength and Conditioning Research
Journal of Sports …, 2006
Parathyroid hormone (PTH) is the major hormone regulating calcium metabolism and is involved in b... more Parathyroid hormone (PTH) is the major hormone regulating calcium metabolism and is involved in both catabolic and anabolic actions on bone. Intermittent PTH exposure can stimulate bone formation and bone mass when PTH has been injected. In contrast, continuous infusion of PTH stimulates bone resorption. PTH concentration may be affected by physical exercise and our review was designed to investigate this relationship. The variation in PTH concentration appears to be influenced by both exercise duration and intensity. There probably exists a stimulation threshold of exercise to alter PTH. PTH regulation is also influenced by the initial bone mineral content, age, gender, training state, and other hormonal and metabolic factors (catecholamines, lactic acid and calcium concentrations).