Balsalobre-Fernández, C, Santos-Concejero, J, and Grivas, GV. Effects of strength training on running economy in highly trained runners: a systematic review with meta-analysis of controlled trials. J Strength Cond Res 30(8): 2361–2368, 2016—The purpose of this study was to perform a systematic review and meta-analysis of controlled trials to determine the effect of strength training programs on the running economy (RE) of high-level middle- and long-distance runners. Four electronic databases were searched in September 2015 (PubMed, SPORTDiscus, MEDLINE, and CINAHL) for original research articles. After analyzing 699 resultant original articles, studies were included if the following criteria were met: (a) participants were competitive middle- or long-distance runners; (b) participants had a V̇o ₂max >60 ml·kg⁻¹·min⁻¹; (c) studies were controlled trials published in peer-reviewed journals; (d) studies analyzed the effects of strength training programs with a duration greater than 4 weeks; and (e) RE was measured before and after the strength training intervention. Five studies met the inclusion criteria, resulting in a total sample size of 93 competitive, high-level middle- and long-distance runners. Four of the 5 included studies used low to moderate training intensities (40–70% one repetition maximum), and all of them used low to moderate training volume (2–4 resistance lower-body exercises plus up to 200 jumps and 5–10 short sprints) 2–3 times per week for 8–12 weeks. The meta-analyzed effect of strength training programs on RE in high-level middle- and long-distance runners showed a large, beneficial effect (standardized mean difference [95% confidence interval] = −1.42 [−2.23 to −0.60]). In conclusion, a strength training program including low to high intensity resistance exercises and plyometric exercises performed 2–3 times per week for 8–12 weeks is an appropriate strategy to improve RE in highly trained middle- and long-distance runners.

The presence of the relative age effect (RAE) has been widely reported; however, its underlying causes have not yet been determined. With this in mind, the present study examined if anthropometry and performance were different amongst older and younger soccer players born in the same year. Eighty-eight young soccer players participated in the study (age 9.75 ± 0.30). Anthropometric measurements, physical tests (sprint, agility, endurance test, jump and hand dynamometry) and the estimation of the maturity status were carried out. Most players (65.9%) were born in the first half of the year. Older players were taller (P < 0.05), had longer legs (P < 0.01) and a larger fat-free mass (P < 0.05). Maturity offset was smaller in the older boys (P < 0.05); however, age at peak height velocity was similar. Older boys performed better in velocity and agility (P < 0.05) and particularly in the overall score of performance (P < 0.01). Stepwise regression analysis revealed that chronological age was the most important variable in the agility test and the overall score, after the skinfolds (negative effect). We report differences in anthropometry and physical performance amongst older and younger pre-pubertal soccer players. These differences may underlie the RAE.

The aim of this study was to analyse the talent identification process of a professional soccer club. A preselection of players (n = 64) aged 9–10 years and a final selection (n = 21) were performed by the technical staff through the observation during training sessions and matches. Also, 34 age-matched players of an open soccer camp (CampP) acted as controls. All participants underwent anthropometric, maturity and performance measurements. Preselected outfield players (OFs) were older and leaner than CampP (P < 0.05). Besides, they performed better in velocity, agility, endurance and jump tests (P < 0.05). A discriminant analysis showed that velocity and agility were the most important parameters. Finally, selected OFs were older and displayed better agility and endurance compared to the nonselected OFs (P < 0.05). Goalkeepers (GKs) were taller and heavier and had more body fat than OFs; also, they performed worse in the physical tests (P < 0.05). Finally, selected GKs were older and taller, had a higher predicted height and advanced maturity and performed better in the handgrip (dynamometry) and jump tests (P < 0.05). Thus, the technical staff selected OFs with a particular anthropometry and best performance, particularly agility and endurance, while GKs had a different profile. Moreover, chronological age had an important role in the whole selection process.

Casado, A, Hanley, B, Santos-Concejero, J, and Ruiz-Pérez, LM. World-class long-distance running performances are best predicted by volume of easy runs and deliberate practice of short-interval and tempo runs. J Strength Cond Res 35(9): 2525–2531, 2021—The aim of this novel study was to analyze the effect of deliberate practice (DP) and easy continuous runs completed by elite-standard and world-class long-distance runners on competitive performances during the first 7 years of their sport careers. Eighty-five male runners reported their best times in different running events and the amounts of different DP activities (tempo runs and short- and long-interval sessions) and 1 non-DP activity (easy runs) after 3, 5, and 7 years of systematic training. Pearson's correlations were calculated between performances (calculated using the International Association of Athletics Federations' scoring tables) and the distances run for the different activities (and overall total). Simple and multiple linear regression analysis calculated how well these activities predicted performance. Pearson's correlations showed consistently large effects on performance of total distance ( r ≥ 0.75, p < 0.001), easy runs ( r ≥ 0.68, p < 0.001), tempo runs ( r ≥ 0.50, p < 0.001), and short-interval training ( r ≥ 0.53, p < 0.001). Long-interval training was not strongly correlated ( r ≥ 0.22). Total distance accounted for significant variance in performance ( R ² ≥ 0.57, p < 0.001). Of the training modes, hierarchical regression analysis showed that easy runs and tempo runs were the activities that accounted for significant variance in performance ( p < 0.01). Although DP activities, particularly tempo runs and short-interval training, are important for improving performance, coaches should note that the non-DP activity of easy running was crucial in better performances, partly because of its contribution to total distance run.

The aim of this study was to analyse the influence of the pacing strategy adopted by elite marathon runners when setting every marathon world record in the last 50 years. We divided former marathon record holders into two groups:classic athletes(record holders between 1967 and 1988) andcontemporaneous athletes(record holders between 1988 and 2018). The total distance of the marathon was divided into 8 sections of 5 km and 1 last section of 2.195 km, and the relative average speed of each section was calculated individually. On average athletes were slightly faster in the first half‐marathon than in the second one, where they slowed down progressively (ES = 0.28, small effect). However, when comparing classic vs. contemporaneous athletes, we observed that classic athletes started significantly faster (p< .05, ES = 1.16, moderate effect), although after 25 km, their speed dropped dramatically and was significantly slower than in their contemporaneous counterparts (ES = 2.41, very large effect). This study shows that the pacing strategies of the best marathon runners in the world have changed over the last 50 years. Although a negative pace distribution has been proposed as the most efficient option, a pacing strategy characterised by very little speed changes across the whole race may be the way to go in the future.

This review aimed to examine the current evidence for 3 primary training intensity distribution types: (1) pyramidal training, (2) polarized training, and (3) threshold training. Where possible, the training intensity zones relative to the goal race pace, rather than physiological or subjective variables, were calculated. Three electronic databases (PubMed, Scopus, and Web of Science) were searched in May 2017 for original research articles. After analysis of 493 resultant original articles, studies were included if they met the following criteria: (1) Their participants were middle- or long-distance runners; (2) they analyzed training intensity distribution in the form of observational reports, case studies, or interventions; (3) they were published in peer-reviewed journals; and (4) they analyzed training programs with a duration of 4 wk or longer. Sixteen studies met the inclusion criteria, which included 6 observational reports, 3 case studies, 6 interventions, and 1 review. According to the results of this analysis, pyramidal and polarized training are more effective than threshold training, although the latest is used by some of the best marathon runners in the world. Despite this apparent contradictory finding, this review presents evidence for the organization of training into zones based on a percentage of goal race pace, which allows for different periodization types to be compatible. This approach requires further development to assess whether specific percentages above and below race pace are key to inducing optimal changes.