The process of maturation is continuous throughout childhood and adolescence. In a biological context, the effects of a child’s maturation might mask or be greater than the effects associated with exposure to exercise. Pediatric exercise scientists must therefore include an assessment of biological age in study designs so that the confounding effects of maturation can be controlled for. In order to understand how maturation can be assessed, it is important to appreciate that 1 year of chronological time is not equivalent to 1 year of biological time. Sex- and age-associated variations in the timing and tempo of biological maturation have long been recognized. This paper reviews some of the possible biological maturity indicators that the pediatric exercise scientist can use. As a result, we recommend that any of the methods discussed could be used for gender-specific comparisons. Gender-comparison studies should either use skeletal age or some form of somatic index.
Adam D. G. Baxter-Jones, Joey C. Eisenmann and Lauren B. Sherar
“Americanization” is a much more useful term than “globalization” in the Canadian context. The specific practices of commercial sport that have eroded local autonomy began as explicitly American practices, and state-subsidized American-based cartels flood the Canadian market with American-focused spectacles, images, and souvenirs. But the term does oversimplify the complexity of social determinations and masks the increasing role the Canadian bourgeoisie plays in continentalist sports. “American capitalist hegemony” is therefore preferable. The long debate over Americanization in Canada has also focused on the appropriate public policy response. Traditionally, Canadians have turned to the state to protect cultural expression from the inroads of American production, but that becomes increasingly difficult under neoconservative renovation and the regional trading bloc created by the 1989 U.S.-Canada Free Trade Agreement. The popular movements will need new means to protect and strengthen the presentation and distribution of their own sporting culture.
Lacey Nordsiden, Bonnie L. Van Lunen, Martha L. Walker, Nelson Cortes, Maria Pasquale and James A. Onate
Many styles of foot pads are commonly applied to reduce immediate pain and pressure under the foot.
To examine the effect of 3 different foot pads on peak plantar pressure (PPP) and mean plantar pressure (MPP) under the first metatarsophalangeal joint (MTPJ) during slow running.
A 4 (pad) × 4 (mask) repeated-measures design.
University athletic training clinic and fitness facility.
20 physically active participants, 12 men (19.7 ± 1.3 y, 181.5 ± 6.3 cm, 83.6 ± 12.3 kg) and 8 women (20.8 ± 1.5 y, 172.7 ± 11.2 cm, 69.9 ± 14.2 kg) with navicular drop greater than or equal to 10 mm, no history of surgery to the lower extremity, and no history of pain or injury to the first MTPJ in the past 6 months.
PPP and MPP were evaluated under 4 areas of the foot: the rear foot, lateral forefoot, medial forefoot, and first MTPJ. Four pad conditions (no pad, metatarsal dome, U-shaped pad, and donut-shaped pad) were evaluated during slow running. All measurements were taken on a standardized treadmill using the Pedar in-shoe pressure-measurement system.
Main Outcome Measures:
PPP and MPP in 4 designated foot masks during slow running.
The metatarsal dome produced significant decreases in MPP (163.07 ± 49.46) and PPP (228.73 ± 63.41) when compared with no pad (P < .001). The U-shaped pad significantly decreased MPP (168.68 ± 50.26) when compared with no pad (P < .001). The donut-shaped pad increased PPP compared with no pad (P < .001).
The metatarsal dome was most effective in reducing both peak and mean plantar pressure. Other factors such as pad comfort, type of activity, and material availability must also be considered. Further research should be conducted on the applicability to other foot types and symptomatic subjects.
Jane LaRiviere and Louis R. Osternig
Ice-induced anesthesia is often used to permit pain-free activity. However, icing before a skilled performance may distort the ability to acknowledge sensory stimuli and may thereby mask certain protective mechanisms. Inadequate peripheral feedback regarding position of a limb in space could expose the joint to injury. This study was designed to determine the effect of ice immersion on ankle joint position sense. Three different pretest conditions of no ice immersion, 5 min of ice immersion, and 20 min of ice immersion were administered to 31 subjects prior to joint angle replication testing with an electrogoniometer. Subjects completed eight repositioning trials (four at each of two test angles) following each condition. An analysis of variance (ANOVA) revealed no statistically significant difference between conditions, trials, or angles. The results suggest that joint position receptors in the ankle are resilient to this type of ice treatment, or that the affected receptors (i.e., skin and muscle) were adequately compensated for by other sensors such as joint receptors.
Matheus M. Gomes and José A. Barela
The purpose of this study was to examine the effects of visual and somatosensory information on body sway in individuals with Down syndrome (DS). Nine adults with DS (19–29 years old) and nine control subjects (CS) (19–29 years old) stood in the upright stance in four experimental conditions: no vision and no touch; vision and no touch; no vision and touch; and vision and touch. In the vision condition, participants looked at a target placed in front of them; in the no vision condition, participants wore a black cotton mask. In the touch condition, participants touched a stationary surface with their right index finger; in the no touch condition, participants kept their arms hanging alongside their bodies. A force plate was used to estimate center of pressure excursion for both anterior-posterior and medial-lateral directions. MANOVA revealed that both the individuals with DS and the control subjects used vision and touch to reduce overall body sway, although individuals with DS still oscillated more than did the CS. These results indicate that adults with DS are able to use sensory information to reduce body sway, and they demonstrate that there is no difference in sensory integration between the individuals with DS and the CS.
Per-Ludvik Kjendlie and Robert Keig Stallman
The aims of this study were to compare drag in swimming children and adults, quantify technique using the technique drag index (TDI), and use the Froude number (Fr) to study whether children or adults reach hull speed at maximal velocity (v max). Active and passive drag was measured by the perturbation method and a velocity decay method, respectively, including 9 children aged 11.7 ± 0.8 and 13 adults aged 21.4 ± 3.7. The children had significantly lower active (k AD) and passive drag factor (k PD) compared with the adults. TDI (k AD/k PD) could not detect any differences in swimming technique between the two groups, owing to the adults swimming maximally at a higher Fr, increasing the wave drag component, and masking the effect of better technique. The children were found not to reach hull speed at v max, and their Fr were 0.37 ± 0.01 vs. the adults 0.42 ± 0.01, indicating adults’ larger wave-making component of resistance at v max compared with children. Fr is proposed as an evaluation tool for competitive swimmers.
Bruce Abernethy and David G. Russell
Two experiments are described comparing the temporal and spatial characteristics of the anticipatory cues used by expert (n=20) and novice (n=35) racquet sport players. In both experiments the perceptual display available in badminton was simulated using film, and display characteristics were selectively manipulated either by varying the duration of the stroke sequence that was visible (Experiment 1) or by selectively masking specific display features (Experiment 2). The subjects* task in all cases was to predict the landing position of the stroke they were viewing. It was found in Experiment 1 that experts were able to pick up more relevant information from earlier display cues than could novices, and this appeared in Experiment 2 to be due to their ability to extract advance information from the playing side arm, in addition to the racquet itself. These differences, it was concluded, were congruent with predictions that could be derived from traditional information-processing notions related to recognition of display redundancy. The roles of different anticipatory cue sources in the independent predictions of stroke speed and direction were also examined, and it was concluded that directional judgments were more dependent on cue specificity than were depth judgments.
Cheryl L. Cole
In this paper l consider how the contemporary national imagination is fabricated through racially coded deviance by interrogating what Nike calls its P.L.A.Y (Participate in the Lives of American Youth) campaign. P.L.A.Y., represented as a practical challenge to recent developments that deny “kids” access to sport and fitness activities, is part of a promotional network through which Nike seeks to secure a patriotic, charitable, and socially responsible public profile. In part, this profile and the complex terrain Nike occupies are territorialized through the somatic identity of Michael Jordan. I argue that representative figures like American Jordan are both effects and instruments of modern power. As such, Jordan is an element in and expression of a discursive formation that works to delimit and render intelligible what/who count as violent, criminal, and dangerous. The regulatory ideals invoked through a nation-centric discourse, American principles, Michael Jordan, and the apparent inverse relationship between urban sport and gangs work to bound and limit identities in ways that mask the complexities of the terrain occupied by transnational corporations like Nike, while exacerbating punitive and vengeful desires directed at Black urban youth.
Judy L. Van Raalte, Lorraine Wilson, Allen Cornelius and Britton W. Brewer
sport of SCUBA diving are particularly interesting, because failure to execute SCUBA diving skills correctly can result in injury or even death. Mask clearing is one of many fundamental SCUBA diving skills. SCUBA divers must clear their masks when water leaks into the mask, which can happen under
Geoff Minett, Rob Duffield and Stephen P. Bird
To investigate the effects of an acute multinutrient supplement on game-based running performance, peak power output, anaerobic by-products, hormonal profiles, markers of muscle damage, and perceived muscular soreness before, immediately after, and 24 h following competitive rugby union games.
Twelve male rugby union players ingested either a comprehensive multinutrient supplement (SUPP), [RE-ACTIVATE:01], or a placebo (PL) for 5 d. Participants then performed a competitive rugby union game (with global positioning system tracking), with associated blood draws and vertical jump assessments pre, immediately post and 24 h following competition.
SUPP ingestion resulted in moderate to large effects for augmented 1st half very high intensity running (VHIR) mean speed (5.9 ± 0.4 vs 4.8 ± 2.3 m·min−1; d = 0.93). Further, moderate increases in 2nd half VHIR distance (137 ± 119 vs 83 ± 89 m; d = 0.73) and VHIR mean speed (5.9 ± 0.6 v 5.3 ± 1.7 m·min−1; d = 0.56) in SUPP condition were also apparent. Postgame aspartate aminotransferase (AST; 44.1 ± 11.8 vs 37.0 ± 3.2 UL; d = 1.16) and creatine kinase (CK; 882 ± 472 vs. 645 ± 123 UL; d = 0.97) measures demonstrated increased values in the SUPP condition, while AST and CK values correlated with 2nd half VHIR distance (r = −0.71 and r = −0.76 respectively). Elevated C-reactive protein (CRP) was observed postgame in both conditions; however, it was significantly blunted with SUPP (P = .05).
These findings suggest SUPP may assist in the maintenance of VHIR during rugby union games, possibly via the buffering qualities of SUPP ingredients. However, correlations between increased work completed at very high intensities and muscular degradation in SUPP conditions, may mask any anticatabolic properties of the supplement.