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Tyler J. Noble and Robert F. Chapman

Purpose: To assess differences in event-specific specialization between elite African and non-African male marathon runners based on age, performance, and career length. Methods: The top 90 African marathoners from 2001 to 2015 were compared with the top 90 non-African marathoners from the same time period across various markers related to specialization age, performance, and career length. Independent t tests were used to identify significant differences (P < .05) between the African and non-African groups. Linear regression was used to explore the relationship between first half-marathon and best full-marathon performance. A 1-way ANOVA and Bonferroni correction was used to assess differences in specialization age and rates of performance improvement and decline. Results: African marathoners were found to specialize, reach peak levels of performance, and retire at younger ages than non-African marathoners (P < .001). In addition, African marathoners were found to be faster at these same career time points and in half-marathon performance (P < .001). There was no significant difference in the number of career marathons run between groups, but African marathoners were found to race more frequently than non-African marathoners (P < .001). Half-marathon performance was positively correlated with marathon performance (r 2 = .67). Marathon athletes who specialized at early ages experienced significantly higher rates of improvement than those who specialized at older ages. (P < .05). Conclusions: The findings suggest that elite African marathoners achieve a greater level of performance at younger ages than their non-African counterparts. Furthermore, current marathon talent-identification practice may benefit from using half-marathon performance.

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Abigail S.L. Stickford, Daniel P. Wilhite and Robert F. Chapman

Investigations into ventilatory, metabolic, and hematological changes with altitude training have been completed; however, there is a lack of research exploring potential gait-kinematic changes after altitude training, despite a common complaint of athletes being a lack of leg "turnover" on return from altitude training.

Purpose:

To determine if select kinematic variables changed in a group of elite distance runners after 4 wk of altitude training.

Methods:

Six elite male distance runners completed a 28-d altitude-training intervention in Flagstaff, AZ (2150 m), following a modified “live high–train low” model, wherein higherintensity runs were performed at lower altitudes (945–1150 m) and low-intensity sessions were completed at higher altitudes (1950–2850 m). Gait parameters were measured 2–9 d before departure to altitude and 1 to 2 d after returning to sea level at running speeds of 300–360 m/min.

Results:

No differences were found in ground-contact time, swing time, or stride length or frequency after altitude training (P > .05).

Conclusions:

Running mechanics are not affected by chronic altitude training in elite distance runners. The data suggest that either chronic training at altitude truly has no effect on running mechanics or completing the live high–train low model of altitude training, where higher-velocity workouts are completed at lower elevations, mitigates any negative mechanical adaptations that may be associated with chronic training at slower speeds.

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Robert F. Chapman, Abigail S. Laymon and Todd Arnold

Subjects with scores on the Functional Movement Screen (FMS) assessment of ≤14 or with at least 1 bilateral asymmetry have been shown to have greater future injury incidence than subjects with FMS scores >14 or no movement asymmetries.

Purpose:

To determine if FMS injury risk factors extend to longitudinal competitive performance outcomes in elite track and field athletes.

Methods:

Elite track and field athletes were examined (N = 121), each completing an FMS before the 2011 competitive season. Best competition marks for the year were obtained from athletes’ actual performances for 2010 and 2011. Performance change between 2010 and 2011 was examined in cohorts of FMS scores ≤14 (LoFMS) vs >14 (HiFMS), athletes with bilateral asymmetry in at least 1 of the 5 FMS movements vs athletes with no asymmetry, and athletes who scored 1 on the deep-squat movement vs athletes who scored 2 or 3.

Results:

HiFMS had a significantly different change in performance from 2010 to 2011 (0.41% ± 2.50%, n = 80) compared with LoFMS (−0.51% ± 2.30%, P = .03, n = 41). Athletes with no asymmetries had a longitudinal improvement in performance (+0.60% ± 2.86%, n = 50) compared with athletes with at least 1 asymmetry (−0.26% ± 2.10%, P = .03, n = 71). Athletes who scored 1 on the deep-squat movement had a significantly different change in performance (−1.07 ± 2.08%, n = 22) vs athletes who scored 2 (0.13% ± 2.28%, P = .03, n = 87) or 3 (1.98% ± 3.31%, P = .001, n = 12).

Conclusion:

Functional movement ability, known to be associated with the likelihood of future injury, is also related to the ability to improve longitudinal competitive performance outcomes.

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Abigail S.L. Stickford, Robert F. Chapman, Jeanne D. Johnston and Joel M. Stager

The efficacy of and mechanisms behind the widespread use of lower-leg compression as an ergogenic aid to improve running performance are unknown. The purpose of this study was to examine whether wearing graduated lower-leg compression sleeves during exercise evokes changes in running economy (RE), perhaps due to altered gait mechanics. Sixteen highly trained male distance runners completed 2 separate RE tests during a single laboratory session, including a randomized-treatment trial of graduated calf-compression sleeves (CS; 15–20 mm Hg) and a control trial (CON) without compression sleeves. RE was determined by measuring oxygen consumption at 3 constant submaximal speeds of 233, 268, and 300 m/min on a treadmill. Running mechanics were measured during the last 30 s of each 4-min stage of the RE test via wireless triaxial 10-g accelerometer devices attached to the top of each shoe. Ground-contact time, swing time, step frequency, and step length were determined from accelerometric output corresponding to foot-strike and toe-off events. Gait variability was calculated as the standard deviation of a given gait variable for an individual during the last 30 s of each stage. There were no differences in VO2 or kinematic variables between CON and CS trials at any of the speeds. Wearing lower-leg compression does not alter the energetics of running at submaximal speeds through changes in running mechanics or other means. However, it appears that the individual response to wearing lower-leg compression varies greatly and warrants further examination.

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Philo U. Saunders, Laura A. Garvican-Lewis, Robert F. Chapman and Julien D. Périard

High-level athletes are always looking at ways to maximize training adaptations for competition performance, and using altered environmental conditions to achieve this outcome has become increasingly popular by elite athletes. Furthermore, a series of potential nutrition and hydration interventions may also optimize the adaptation to altered environments. Altitude training was first used to prepare for competition at altitude, and it still is today; however, more often now, elite athletes embark on a series of altitude training camps to try to improve sea-level performance. Similarly, the use of heat acclimation/acclimatization to optimize performance in hot/humid environmental conditions is a common practice by high-level athletes and is well supported in the scientific literature. More recently, the use of heat training to improve exercise capacity in temperate environments has been investigated and appears to have positive outcomes. This consensus statement will detail the use of both heat and altitude training interventions to optimize performance capacities in elite athletes in both normal environmental conditions and extreme conditions (hot and/or high), with a focus on the importance of nutritional strategies required in these extreme environmental conditions to maximize adaptations conducive to competitive performance enhancement.

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Daniel G. Hursh, Marissa N. Baranauskas, Chad C. Wiggins, Shane Bielko, Timothy D. Mickleborough and Robert F. Chapman

Endurance exercise performance in hypoxia may be influenced by an ability to maintain high minute ventilation (V˙E) in defense of reduced arterial oxyhemoglobin saturation. Inspiratory muscle training (IMT) has been used as an effective intervention to attenuate the negative physiological consequences associated with an increased V˙E, resulting in improved submaximal-exercise performance in normoxia. However, the efficacy of IMT on hypoxic exercise performance remains unresolved. Purpose: To determine whether chronic IMT improves submaximal-exercise performance with acute hypoxic exposure. Methods: A total of 14 endurance-trained men completed a 20-km cycling time trial (TT) in normobaric hypoxia (fraction of inspired oxygen [FiO2] = 0.16) before and after either 6 wk of an IMT protocol consisting of inspiratory loads equivalent to 80% of sustained maximal inspiratory pressure (n = 9) or a SHAM protocol (30% of sustained maximal inspiratory pressure; n = 5). Results: In the IMT group, 20-km TT performance significantly improved by 1.45 (2.0%), P = .03, after the 6-wk intervention. The significantly faster TT times were accompanied by a higher average V˙E (pre vs post: 99.3 [14.5] vs 109.9 [18.0] L·min−1, P = .01) and absolute oxygen uptake (pre vs post: 3.39 [0.52] vs 3.60 [0.58] L·min−1, P = .010), with no change in ratings of perceived exertion or dyspnea (P > .06). There were no changes in TT performance in the SHAM group (P = .45). Conclusion: These data suggest that performing 6 wk of IMT may benefit hypoxic endurance exercise performance lasting 30–40 min.