Mountain marathons are 2-d, self-supported adventure races, during which competitors must carry all nutritional requirements to sustain athletic effort. This requires a compromise between the energy required to perform and the weight penalty of carrying it. We have undertaken a nutritional survey of event competitors in the UK using a questionnaire-based approach and have monitored dehydration during the event. We found that competitors in longer-distance classes (> 50 km) carry significantly less mass of food, which is more energy dense, but that the calorific value is lower than that of competitors in shorter classes. Carbohydrate and protein consumption both positively associated with performance. Competitors became progressively dehydrated throughout the event. Counterintuitively, the better-performing subjects became the most dehydrated. Competitors at all distances should make more effort to rehydrate during breaks in the event. Competitors at shorter distances could choose more energy-dense foods to reduce weight penalty.
Heather R. Clark, Margo E. Barker and Bernard M. Corfe
Kirsten Krahnstoever Davison
A comprehensive measure of activity-related support was developed and used to examine gender differences in activity support and links between support and physical activity in a sample of adolescents.
Participants included 202 middle school girls and boys. Participants completed the Activity Support Scale and three self-report measures of physical activity.
Seven sources of support were identified including maternal and paternal logistic support, maternal and paternal modelling, general familial support, sibling support, and peer support; all scales were internally consistent. No gender differences in activity-related support were identified. Adolescents who were more active reported higher levels of activity support from all sources except maternal and paternal modelling of physical activity.
Results from this study highlight the importance of activity-related support from family and friends as a potential method to promote and sustain physical activity among adolescents.
Ka-Chun Siu, Shireen S. Rajaram and Carolina Padilla
Increasing evidence underscores the health benefits of Tai Chi (TC), although there is limited evidence of benefits among racial and ethnic minorities. This study investigated the impact of psychosocial status on balance among 23 Latino seniors after a twice-a-week, 12-week TC exercise program. Functional status was measured at baseline, immediately after, and three months following the TC exercise program, using the Timed Up and Go Test and Tinetti Falls Efficacy Scale. Psychosocial status was measured at baseline by the Center for Epidemiologic Studies Depression Scale and Norbeck Social Support Questionnaire. Both measures of functional status improved and were sustained after three months of TC. Greater improvement was significantly related to a higher level of baseline social support. More depressed seniors reported less fear of falling after TC. Depression and social support are important moderators of functional improvement after TC among Latino seniors.
Shane R. Wurdeman, Jessie M. Huisinga, Mary Filipi and Nicholas Stergiou
Patients with multiple sclerosis (MS) have less-coordinated movements of the center of mass resulting in greater mechanical work. The purpose of this study was to quantify the work performed on the body’s center of mass by patients with MS. It was hypothesized that patients with MS would perform greater negative work during initial double support and less positive work in terminal double support. Results revealed that patients with MS perform less negative work in single support and early terminal double support and less positive work in the terminal double support period. However, summed over the entire stance phase, patients with MS and healthy controls performed similar amounts of positive and negative work on the body’s center of mass. The altered work throughout different periods in the stance phase may be indicative of a failure to capitalize on passive elastic energy mechanisms and increased reliance upon more active work generation to sustain gait.
As the incidence of childhood obesity increases, there is a need to promote leisure time physical activity. Traditional approaches to promote the population physical activity levels have shown at best moderate improvements. High percentage of children today carry a cell phone, thus the use of this portable device seems promising for enhancing physical activity.
Pokémon Go, is a smartphone game that uses augmented reality, where players are incentivized to get out and walk significant distances to catch the Pokémon. Initial reports suggested increases in the number of steps that players performed, yet this effect of the game was not sustained. Incorporating physical activity into modern technology seems promising, clearly there is need to explore creative ways to achieve a longer term effect.
Ben Desbrow, Nicholas A. Burd, Mark Tarnopolsky, Daniel R. Moore and Kirsty J. Elliott-Sale
Adolescent, female, and masters athletes have unique nutritional requirements as a consequence of undertaking daily training and competition in addition to the specific demands of age- and gender-related physiological changes. Dietary education and recommendations for these special population athletes require a focus on eating for long-term health, with special consideration given to “at-risk” dietary patterns and nutrients (e.g., sustained restricted eating, low calcium, vitamin D and/or iron intakes relative to requirements). Recent research highlighting strategies to address age-related changes in protein metabolism and the development of tools to assist in the management of Relative Energy Deficiency in Sport are of particular relevance to special population athletes. Whenever possible, special population athletes should be encouraged to meet their nutrient needs by the consumption of whole foods rather than supplements. The recommendation of dietary supplements (particularly to young athletes) overemphasizes their ability to manipulate performance in comparison with other training/dietary strategies.
Katherine A. Beals and Melinda M. Manore
This study examined the prevalence of and relationship between the disorders of the female athlete triad in collegiate athletes participating in aesthetic, endurance, or team/anaerobic sports. Participants were 425 female collegiate athletes from 7 universities across the United States. Disordered eating, menstrual dysfunction, and musculoskeletal injuries were assessed by a health/medical, dieting and menstrual history questionnaire, the Eating Attitudes Test (EAT-26), and the Eating Disorder Inventory Body Dissatisfaction Subscale (EDI-BD). The percentage of athletes reporting a clinical diagnosis of anorexia and bulimia nervosa was 3.3% and 2.3%, respectively; mean (±SD) EAT and EDI-BD scores were 10.6 ± 9.6 and 9.8 ± 7.6, respectively. The percentage of athletes with scores indicating “at-risk” behavior for an eating disorder were 15.2% using the EAT-26 and 32.4% using the EDI-BD. A similar percentage of athletes in aesthetic, endurance, and team/anaerobic sports reported a clinical diagnosis of anorexia or bulimia. However, athletes in aesthetic sports scored higher on the EAT-26 (13.5 ± 10.9) than athletes in endurance (10.0 ± 9.3) or team/anaerobic sports (9.9 ± 9.0, p < .02); and more athletes in aesthetic versus endurance or team/anaerobic sports scored above the EAT-26 cut-off score of 20 (p < .01). Menstrual irregularity was reported by 31% of the athletes not using oral contraceptives, and there were no group differences in the prevalence of self-reported menstrual irregularity. Muscle and bone injuries sustained during the collegiate career were reported by 65.9% and 34.3% of athletes, respectively, and more athletes in aesthetic versus endurance and team/anaerobic sports reported muscle (p = .005) and/or bone injuries (p < .001). Athletes “at risk” for eating disorders more frequently reported menstrual irregularity (p = .004) and sustained more bone injuries (p = .003) during their collegiate career. These data indicate that while the prevalence of clinical eating disorders is low in female collegiate athletes, many are “at risk” for an eating disorder, which places them at increased risk for menstrual irregularity and bone injuries.
Arthur H. Bossi, Cristian Mesquida, Louis Passfield, Bent R. Rønnestad and James G. Hopker
particularly in the case of well-trained athletes. 1 – 3 Therefore, accumulating time at or close to V ˙ O 2 max (eg, >90% or >95%) during a HIIT session may be important for training adaptation. 1 – 4 , 6 – 9 Previously, Billat et al 10 have demonstrated that the ability to sustain exercise at > 95 % V
Randall L. Wilber
“Live high-train low” (LH+TL) altitude training allows athletes to “live high” for the purpose of facilitating altitude acclimatization, as characterized by a significant and sustained increase in endogenous erythropoietin and subsequent increase in erythrocyte volume, while simultaneously enabling them to “train low” for the purpose of replicating sea-level training intensity and oxygen flux, thereby inducing beneficial metabolic and neuromuscular adaptations. In addition to natural/terrestrial LH+TL, several simulated LH+TL devices have been developed including nitrogen apartments, hypoxic tents, and hypoxicator devices. One of the key issues regarding the practical application of LH+TL is what the optimal hypoxic dose is that is needed to facilitate altitude acclimatization and produce the expected beneficial physiological responses and sea-level performance effects. The purpose of this review is to examine this issue from a research-based and applied perspective by addressing the following questions: What is the optimal altitude at which to live, how many days are required at altitude, and how many hours per day are required? It appears that for athletes to derive the hematological benefits of LH+TL while using natural/terrestrial altitude, they need to live at an elevation of 2000 to 2500 m for >4 wk for >22 h/d. For athletes using LH+TL in a simulated altitude environment, fewer hours (12-16 h) of hypoxic exposure might be necessary, but a higher elevation (2500 to 3000 m) is required to achieve similar physiological responses.
David E. Krebs, Peter H. Velyvis and Mark W. Rogers
This study examined the prevalence of protective stepping and accompanying preparatory postural responses associated with lateral weight transfer (WT) while subjects attempted to sustain stationary standing. The subjects were 92 healthy young and older adults and persons with vestibular hypo-function. Force platform and whole-body-motion recordings were used to evaluate the prevalence of stepping and WT responses during stationary standing (eyes open or closed) using a semi-tandem foot position. WT components were also evaluated for volitionally requested step initiation, and as a function of support base configuration and direction of stepping among younger subjects. Only 10% of trials by subjects with bilateral vestibular hypofunction (BVH) during semi-tandem standing with eyes closed were completed without a step, while 31% of subjects with UVH, 69% of healthy elders, and all young healthy subjects were able to stand for the entire 7-sec trials. WT responses always preceded volitional steps from a standard feet-parallel orientation but occurred in only 13% of the spontaneous steps. The prevalence of WT was influenced by the direction of volitional stepping from semi-tandem standing, but not by the initial standing width. Spontaneous stepping to maintain standing balance is a naturally occurring and prevalent behavior among older adults and persons with vestibular hypo-function during tests of quasi-static standing. Differences between volitional and spontaneous step initiation involving the prevalence of preparatory lateral WT are a complex function of motor planning, mechanical constraints, and functional context.