Vitamin D and Cortisol as Moderators of the Relationship Between Testosterone and Exercise Performance in Adolescent Male Athletes

2020 ◽  
Vol 32 (4) ◽  
pp. 204-209 ◽  
Author(s):  
Blair Crewther ◽  
Christian Cook ◽  
John Fitzgerald ◽  
Michal Starczewski ◽  
Michal Gorski ◽  
...  
Keyword(s):  
Effect Size ◽  
Exercise Performance ◽  
Muscle Power ◽  
Ice Hockey ◽  
Adolescent Male ◽  
Countermovement Jump ◽  
Cross Sectional ◽  
Male Athletes ◽  
Complex Interactions ◽  
Jump Power

Purpose: Reported associations between vitamin 25(OH)D and exercise performance are equivocal, perhaps due to complex interplay with cortisol and testosterone. In this study, the authors investigated serum 25(OH)D and cortisol as moderators of the testosterone relationship with exercise performance in adolescent male athletes. Methods: A total of 88 ice hockey players were assessed for serum 25(OH)D, cortisol, testosterone, body composition, and exercise performance, based on countermovement jump power and muscle torque. The authors tested independent relationships, before examining complex interactions via moderated regression analyses. Results: Most athletes (62.5%) exhibited a suboptimal (20–30 ng·mL−1) serum 25(OH)D concentration, whereas 9.1% of athletes were deficient (<20 ng·mL−1). Serum 25(OH)D was not related to performance when controlling for testing year, age, and fat mass. Further modeling revealed a significant hormonal interaction. Specifically, in low-25(OH)D subjects, testosterone predicted countermovement jump power at a high (β = 7.10, effect size = .43, P < .01), but not low (β = −3.32, effect size = −.20, P = .09), cortisol concentration. Conclusions: Serum 25(OH)D was a poor predictor of exercise performance, but it did moderate (with cortisol) the testosterone link to muscle power. Notably, this relationship emerged among individuals with a 25(OH)D concentration (∼22 ng·mL−1) approaching the deficiency cutoff. Viewing 25(OH)D as a moderating, rather than dose responsive, variable could help explain equivocal cross-sectional associations.

scholarly journals Prevalence of Jumper's Knee among Elite Athletes from Different Sports: A Cross-sectional Study

2005 ◽  
Vol 33 (4) ◽  
pp. 561-567 ◽  
Author(s):  
Østein B. Lian ◽  
Lars Engebretsen ◽  
Roald Bahr
Keyword(s):  
Female Athletes ◽  
Cross Sectional Study ◽  
Ice Hockey ◽  
Sectional Study ◽  
Jumper’S Knee ◽  
Cross Sectional ◽  
Male Athletes ◽  
Male And Female ◽  
Assessment Score ◽  
Significant Difference

Background The prevalence of jumper's knee across different sports has not been examined, and it is not known if there is a gender difference. Data from surgical case series indicate that there may be a high prevalence in sports with high speed and power demands. Hypothesis The aim of this study was to estimate the prevalence of jumper's knee in different sports among female and male athletes and to correlate the prevalence to the loading characteristics of the extensor mechanism in these sports. Study Design Cross-sectional study; Level of evidence, 4. Methods The authors examined approximately 50 Norwegian male and female athletes at the national elite level from each of the following 9 sports: athletics (male athletes: high jump, 100- and 200-m sprint), basketball (male athletes), ice hockey (male athletes), volleyball (male athletes), orienteering (male athletes), road cycling (male athletes), soccer (male and female athletes), team handball (male and female athletes), and wrestling (male athletes). The examination included an interview on individual characteristics (weight, age, height, and training background), a clinical examination, and self-recorded Victorian Institute of Sport Assessment score from 0 (worst) to 100 (best). Results The overall prevalence of current jumper's knee was 14.2% (87 of 613 athletes), with a significant difference between sports with different performance characteristics (range, 0%-45%). In addition, 51 athletes (8%) reported previous symptoms. The prevalence of current symptoms was highest in volleyball (44.6% ± 6.6%) and basketball (31.9% ± 6.8%), whereas there were no cases in cycling or orienteering. The prevalence of current jumper's knee was lower among women (5.6% ± 2.2%) compared with men (13.5% ± 3.0%; χ2 test, P =. 042). The duration of symptoms among athletes with current jumper's knee (n = 87) was 32 ± 25 (standard deviation) months, with a Victorian Institute of Sport Assessment score of 64 ± 19. Conclusion The prevalence of jumper's knee is high in sports characterized by high demands on speed and power for the leg extensors. The symptoms are often serious, resulting in long-standing impairment of athletic performance.

scholarly journals Acute Effects of Different Postactivation Potentiation Protocols on Traditional Rowing Performance

2020 ◽  
Vol 18 (1) ◽  
pp. 80
Author(s):  
Alfonso Penichet-Tomas ◽  
Jose M. Jimenez-Olmedo ◽  
Luis Serra Torregrosa ◽  
Basilio Pueo
Keyword(s):  
Effect Size ◽  
Muscle Power ◽  
Average Power ◽  
Postactivation Potentiation ◽  
Warm Up ◽  
Maximal Load ◽  
Rowing Performance ◽  
Load Intensity ◽  
And Performance ◽  
Student’S T

Postactivation potentiation (PAP) describes an initial muscular activation with a submaximal or maximal load intensity that produces acute improvements in muscle power and performance in subsequent explosive activities. The objective of this study was to compare the effect of different PAP protocols in rowing performance. A crossover design involving seven rowers was used, in which two different PAP protocols were applied: PAP of maximal conditioning contractions (PAP MCC) on a rowing ergometer to provide greater transferability and, thus, enhance the magnitude of PAP stimuli on subsequent rowing performance; and PAP of maximal strength contractions (PAP MSC) in half squat and bench pull exercises, similar to the main exercises in rowing strength training, to perform a 20 s “all-out” test simulating a competition start. Student’s t-test was used to compare means of the variables (p < 0.05). Effect size statistics were calculated using Cohen’s d. The PAP MCC protocol resulted in significant differences, with an extremely large effect size in average power output (p = 0.034, d = 0.98) in the first 3 (p = 0.019, d = 1.15) and first 5 (p = 0.036, d = 0.91) strokes. This group also reached a greater number of strokes (p = 0.049, d = 2.29) and strokes per minute (p = 0.046, d = 1.15). PAP with maximal conditioning contractions in rowing warm-up enhanced subsequent rowing sprint and is an advisable strategy to potentiate performance at the start of rowing competitions and sprint regattas.

scholarly journals Muscular Strength Spurts in Adolescent Male Basketball Players: The INEX Study

2021 ◽  
Vol 18 (2) ◽  
pp. 776
Author(s):  
Eduardo Guimarães ◽  
José A. R. Maia ◽  
Mark Williams ◽  
Filipa Sousa ◽  
Eduardo Santos ◽  
...  
Keyword(s):  
Muscular Strength ◽  
Handgrip Strength ◽  
Height Velocity ◽  
Adolescent Male ◽  
Strength Development ◽  
Maximal Velocity ◽  
Countermovement Jump ◽  
Basketball Players ◽  
Squat Jump ◽  
Medicine Ball

Although successful performance in basketball requires high levels of muscular strength during adolescence, its development is confounded by the effects of normal growth. We examine the timing, intensity and sequence of muscular strength according to biological age (years from peak height velocity (PHV)) and hypothesize that young basketball players attain their peak muscular strength spurts around PHV. A total of 160 adolescent male basketballers, aged 11–15 years, were followed bi-annually over 3 consecutive years. The years from attainment of PHV and peak weight velocity (PWV) were estimated and five muscular strength measures (sit-ups, handgrip, seated medicine ball throw, squat jump and countermovement jump) were aligned to years from PHV in 3-month intervals. Strength velocities were estimated using a non-smooth mathematical model. The mean ages at-PHV and at-PWV were 13.90 ± 1.40 years and 13.90 ± 1.79 years, respectively. Maximal velocity in sit-ups was attained 6 months prior to attainment of PHV (intensity = 10.69 repetitions·year−1), whereas maximal velocity in squat jump occurred 6 months after-PHV (intensity = 3.93 cm·year−1). Handgrip strength, seated medicine ball throw and countermovement jump maximal velocity peaked at-PHV (intensity = 8.47 kgf·year−1, intensity = 0.75 m·year−1, intensity = 5.59 cm·year−1, respectively). In general, maximal velocity spurts did not differ in their timing, with the velocities reaching a peak concurrent with PHV and PWV or within 6 months of its attainment. Basketball coaches, as well as strength and conditioning trainers, should consider individual differences in strength development and be aware of rapid periods of growth in stature when planning and designing muscular strength training regimes.

scholarly journals The effect of breakfast on appetite regulation, energy balance and exercise performance

2015 ◽  
Vol 75 (3) ◽  
pp. 319-327 ◽  
Author(s):  
David J. Clayton ◽  
Lewis J. James
Keyword(s):  
Energy Balance ◽  
Energy Expenditure ◽  
Energy Intake ◽  
Exercise Performance ◽  
Intervention Studies ◽  
Precise Determination ◽  
Positive Energy ◽  
Cross Sectional ◽  
Positive Energy Balance ◽  
The Impact

The belief that breakfast is the most important meal of day has been derived from cross-sectional studies that have associated breakfast consumption with a lower BMI. This suggests that breakfast omission either leads to an increase in energy intake or a reduction in energy expenditure over the remainder of the day, resulting in a state of positive energy balance. However, observational studies do not imply causality. A number of intervention studies have been conducted, enabling more precise determination of breakfast manipulation on indices of energy balance. This review will examine the results from these studies in adults, attempting to identify causal links between breakfast and energy balance, as well as determining whether consumption of breakfast influences exercise performance. Despite the associations in the literature, intervention studies have generally found a reduction in total daily energy intake when breakfast is omitted from the daily meal pattern. Moreover, whilst consumption of breakfast supresses appetite during the morning, this effect appears to be transient as the first meal consumed after breakfast seems to offset appetite to a similar extent, independent of breakfast. Whether breakfast affects energy expenditure is less clear. Whilst breakfast does not seem to affect basal metabolism, breakfast omission may reduce free-living physical activity and endurance exercise performance throughout the day. In conclusion, the available research suggests breakfast omission may influence energy expenditure more strongly than energy intake. Longer term intervention studies are required to confirm this relationship, and determine the impact of these variables on weight management.

scholarly journals Anxiety is associated with diminished exercise performance and quality of life in severe emphysema: a cross-sectional study

2010 ◽  
Vol 11 (1) ◽  
Author(s):  
Nicholas D Giardino ◽  
◽  
Jeffrey L Curtis ◽  
Adin-Cristian Andrei ◽  
Vincent S Fan ◽  
...  
Keyword(s):  
Quality Of Life ◽  
Exercise Performance ◽  
Cross Sectional Study ◽  
Sectional Study ◽  
Cross Sectional ◽  
Severe Emphysema

Reliability, Validity, and Performance Characteristics of Elite Adolescent Athletes at Different Stages of Maturityin the 10 to 5 Repeated Jump Test

2021 ◽  
pp. 1-8
Author(s):  
James Baker ◽  
Barry Shillabeer ◽  
Christopher Brandner ◽  
Philip Graham-Smith ◽  
Patrick Mills ◽  
...  
Keyword(s):  
Correlation Coefficient ◽  
Intraclass Correlation Coefficient ◽  
Intraclass Correlation ◽  
Performance Characteristics ◽  
Height Velocity ◽  
Adolescent Male ◽  
Male Athletes ◽  
Reliable Test ◽  
Jump Test ◽  
And Performance

Purpose: To examine the reliability, validity, and performance characteristics of the 10 to 5 repeated jump test (10–5 RJT) in adolescent male athletes. The 10–5 RJT has been shown to be a valid and reliable test of reactive strength index (RSI) in older adolescents (age 17–19 y), but less is known in younger adolescent athletes at different stages of maturity. Methods: Athletes (age 11–17 y) completed the 10–5 RJT on 2 days, 1 week apart, to examine the reliability (n = 41), validity (n = 18) of the test. Athletes were classified as pre, circa, or post peak height velocity (PHV) height velocity using maturity offset to examine the effect of maturation status on RSI, flight time (FT), ground contact time (GCT), and jump height (JH) (n = 68) using a cross-sectional design. Results: Paired samples t tests showed no significant differences (P ≥ .05), and Bland–Altman analysis showed no bias and close limits of agreement for RSI, JH, FT, and GCT between the contact mat and force plate. Interday reliability was rated excellent for RSI (intraclass correlation coefficient = .91) and good for GCT, FT, and JH (intraclass correlation coefficient = .81–.85). All variables had a coefficient of variation ≤ 10%. RSI increased across maturation groups, with significant differences between pre-PHV and post-PHV groups (P = .014, d = 1.00). Conclusion: The 10–5 RJT is a valid and reliable test for adolescent male athletes. Greater RSI with advancing maturity was primarily due to increased FT and JH, with GCT remaining similar.

scholarly journals Trends in reporting of mechanisms and incidence of hip injuries in males playing minor ice hockey in Canada: a cross-sectional study

2014 ◽  
pp. 143 ◽  
Author(s):  
Marcin Kowalczuk ◽  
Olufemi Ayeni ◽  
Jordan Farag ◽  
Forough Farrokhyar ◽  
Raymond Chu ◽  
...  
Keyword(s):  
Cross Sectional Study ◽  
Ice Hockey ◽  
Sectional Study ◽  
Cross Sectional ◽  
Hip Injuries

scholarly journals The Perceived Demands of Ice Hockey Goaltending Movements on the Hip and Groin Region: An Elite Coach and Player Perspective

2021 ◽  
Vol 9 (11) ◽  
pp. 232596712110556
Author(s):  
Tobias Wörner ◽  
Ryan J. Frayne ◽  
Thomas Magnusson ◽  
Frida Eek
Keyword(s):  
Injury Prevention ◽  
Study Design ◽  
Online Survey ◽  
Likert Scale ◽  
Ice Hockey ◽  
Cross Sectional Survey ◽  
Hip Joints ◽  
Chi Square ◽  
Cross Sectional ◽  
Chi Square Test

Background: Many ice hockey goaltending techniques force hip joints and groin muscles into extreme ranges of motion, which may increase the risk of hip and groin problems. Purpose: To explore how elite goaltenders and goaltending coaches perceive the demands of common goaltending techniques on the hip and groin region. We further explored differences in perception between goaltenders and their coaches as well as between junior (age <20 years) and senior (age ≥20 years) goaltenders. Study Design: Cross-sectional survey. Methods: We developed a model to categorize common ice hockey goaltending techniques into quantifiable units and invited elite goaltenders and coaches in Sweden to complete an online survey. Participants were asked to rate the perceived demands of each technique on the hip and groin using a Likert scale (not at all, slightly, somewhat, very, or extremely demanding). Using the chi-square test, the proportion of participants perceiving each technique as very or extremely demanding were compared between goaltenders and coaches as well as between senior and junior goaltenders. Results: We received responses from 132 goaltenders and 43 coaches. The stances most frequently perceived as very or extremely demanding were the reverse vertical horizontal post-play (40%) and the butterfly save (25%). Among transitions, movements into the post were most frequently rated as very or extremely demanding (11%–40%). Several techniques were perceived as demanding by a larger share of coaches than goaltenders (difference, 13%–46%; P < .001–.028) and a larger share of senior versus junior goaltenders (difference, 12%–20%; P = .13–.18). Conclusion: The post-play and the butterfly were the goaltending techniques most frequently perceived as demanding, and more coaches than goaltenders percieved these techniques demanding. The results of this study may inform injury prevention efforts for ice hockey goaltending.

scholarly journals Out-of-Pocket Spending for Cancer Medication, Financial Burden, and Cost Communication with Oncologists in the Last Six Months of Life in Israel

Healthcare ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 1120
Author(s):  
Aviad Tur-Sinai ◽  
Netta Bentur ◽  
Damien Urban
Keyword(s):  
Private Health Insurance ◽  
Financial Burden ◽  
Female Gender ◽  
Cross Sectional Survey ◽  
Cross Sectional ◽  
Complex Interactions ◽  
The Cost ◽  
Treatment Alternatives ◽  
Financial Burden Of Cancer ◽  
Heavy Financial Burden

Honest communication between oncologists and patients is important in alleviating the financial burden of cancer care. This study explored patient–relative–oncologist communication regarding the affordability of out-of-pocket (OOP) medication and the extent to which this communication addresses itself to the families’ financial burden. A cross-sectional survey was conducted among primary caregivers of deceased cancer patients. About 43% of relatives said that they and/or the patients had paid out of pocket for medications during the last six months of the patient’s life. Most (73%) oncologists suggested an OOP medication without asking about financial ability, 43% hardly explained the advantages of an OOP medication, and 52% hardly explained any treatment alternatives. Older age and female gender were related to less communication about an OOP medication, and better education, greater affluence, and having private health insurance were related to more communication. About 56% of relatives said that OOP payment for medications inflicted a very heavy or heavy financial burden on patients and their households. Physicians’ interest in financial ability and giving explanation lightened the burden. Given the difficulty of explaining the complex interactions of cost and clinical outcomes, oncologists need to be better educated in skills that would enable them to communicate costs more openly and should consider the cost of a treatment when prescribing it.

Statistical Techniques for Interpreting Body Size–Related Exercise Performance during Growth

2000 ◽  
Vol 12 (2) ◽  
pp. 112-127 ◽  
Author(s):  
Joanne R. Welsman ◽  
Neil Armstrong
Keyword(s):  
Body Size ◽  
Linear Regression ◽  
Body Mass ◽  
Exercise Performance ◽  
Multilevel Regression ◽  
Cross Sectional ◽  
Regression Techniques ◽  
Ontogenetic Allometry ◽  
Log Linear ◽  
Individual Size

This paper reviews some of the statistical methods available for controlling for body size differences in the interpretation of developmental changes in exercise performance. For cross-sectional data analysis simple per body mass ratio scaling continues to be widely used, but is frequently ineffective as the computed ratio remains correlated with body mass. Linear regression techniques may distinguish group differences more appropriately but, as illustrated, only allometric (log-linear regression) scaling appropriately removes body size differences while accommodating the heteroscedasticity common in exercise performance data. The analysis and interpretation of longitudinal data within an allometric framework is complex. More established methods such as ontogenetic allometry allow insights into individual size-function relationships but are unable to describe adequately population effects or changes in the magnitude of the response. The recently developed multilevel regression modeling technique represents a flexible and sensitive solution to such problems allowing both individual and group responses to be modeled concurrently.

Sign in / Sign up

Export Citation Format

Share Document