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The aim of this study was to determine whether gait cycle characteristics are associated with running economy in elite Kenyan runners. Fifteen elite Kenyan male runners completed two constant-speed running sets on a treadmill (12 km ·h−1and 20 km ·h−1).VO2and respiratory exchange ratio values were measured to calculate steady-state oxygen and energy cost of running. Gait cycle characteristics and ground contact forces were measured at each speed. Oxygen cost of running at different velocities was 192.2 ± 14.7 ml· kg−1· km−1at 12 km· h−1and 184.8 ± 9.9 ml· kg−1· km−1at 20 km· h−1, which corresponded to a caloric cost of running of 0.94 ± 0.07 kcal ·kg−1·km−1and 0.93 ± 0.07 kcal· kg−1· km−1. We found no significant correlations between oxygen and energy cost of running and biomechanical variables and ground reaction forces at either 12 or 20 km· h−1. However, ground contact times were ~10.0% shorter (very large effect) than in previously published literature in elite runners at similar speeds, alongside an 8.9% lower oxygen cost (very large effect). These results provide evidence to hypothesise that the short ground contact times may contribute to the exceptional running economy of Kenyan runners. [ABSTRACT FROM AUTHOR]

The purpose of the study was to examine the effect of age on short-term performance indicators applying multilevel regression modeling, and whether changes induced by age were affected by maturation. The study applied a mixed longitudinal approach with 8 measurement points over a period of 4 years. Anthropometry, predicted adult stature, countermovement jump, 15-m sprint and agility test from 38 under-11 young soccer players were considered. Early maturing players were 3% taller compared to late maturers. A substantial effect of age was present in all performance indicators (P<0.05). Parameters showed improvements in performance, even when accounting for interindividual variation in somatic maturity. Vertical jump tended to be stable in early maturers during the first year, presenting an exponential increase thereafter (16%, P<0.05). Additionally, early maturing boys had lower vertical jump scores but a substantial higher rate of development with age (3% per year). Performance tends to plateau during the first 3 years following the improvements in agility (9.1%, P<0.05). In the running tests, early maturers had better performances (19%, P<0.05), while a higher rate of improvement of 1% was observed for the late maturers. Young soccer players should be expected to have substantial improvements in short-term performance, influenced by independent variation between players in maturity status. [ABSTRACT FROM AUTHOR]

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The International Olympic Committee (IOC) recently published a framework on fairness, inclusion, and nondiscrimination on the basis of gender identity and sex variations. Although we appreciate the IOC's recognition of the role of sports science and medicine in policy development, we disagree with the assertion that the IOC framework is consistent with existing scientific and medical evidence and question its recommendations for implementation. Testosterone exposure during male development results in physical differences between male and female bodies; this process underpins male athletic advantage in muscle mass, strength and power, and endurance and aerobic capacity. The IOC's "no presumption of advantage" principle disregards this reality. Studies show that transgender women (male-born individuals who identify as women) with suppressed testosterone retain muscle mass, strength, and other physical advantages compared to females; male performance advantage cannot be eliminated with testosterone suppression. The IOC's concept of "meaningful competition" is flawed because fairness of category does not hinge on closely matched performances. The female category ensures fair competition for female athletes by excluding male advantages. Case-by-case testing for transgender women may lead to stigmatization and cannot be robustly managed in practice. We argue that eligibility criteria for female competition must consider male development rather than relying on current testosterone levels. Female athletes should be recognized as the key stakeholders in the consultation and decision-making processes. We urge the IOC to reevaluate the recommendations of their Framework to include a comprehensive understanding of the biological advantages of male development to ensure fairness and safety in female sports., (© 2024 The Authors. Scandinavian Journal of Medicine & Science In Sports published by John Wiley & Sons Ltd.)

There is a growing interest in studies involving carbohydrate (CHO) manipulation and subsequent adaptations to endurance training. This study aimed to analyze whether a periodized carbohydrate feeding strategy based on a daily training session has any advantages compared to a high-carbohydrate diet in well-trained cyclists. Seventeen trained cyclists ( V O 2peak = 70.8 ± 6.5 mL·kg -1 ·min -1 ) were divided into two groups, a periodized (PCHO) group and a high-carbohydrate (HCHO) group. Both groups performed the same training sessions for five weeks. In the PCHO group, 13 training sessions were performed with low carbohydrate availability. In the HCHO group, all sessions were completed following previous carbohydrate intake to ensure high pre-exercise glycogen levels. In both groups, there was an increase in the maximal lactate steady state (MLSS) (PCHO: 244.1 ± 29.9 W to 253.2 ± 28.4 W; p = 0.008; HCHO: 235.8 ± 21.4 W to 246.9 ± 16.7 W; p = 0.012) but not in the time to exhaustion at MLSS intensity. Both groups increased the percentage of muscle mass (PCHO: p = 0.021; HCHO: p = 0.042) and decreased the percent body fat (PCHO: p = 0.021; HCHO: p = 0.012). We found no differences in carbohydrate or lipid oxidation, heart rate, and post-exercise lactate concentration. Periodizing the CHO intake in well-trained cyclists during a 5-week intervention did not elicit superior results to an energy intake-matched high-carbohydrate diet in any of the measured outcomes.

A regular endurance training program may elicit different adaptations compared to an isolated training method. In this study, we analyzed the effects of 8 weeks of a regular endurance training program on running economy (RE), particularly neuromuscular and biomechanical parameters, in runners of different athletic abilities. Twenty-four male runners were divided into two groups: well-trained ( n= 12) and recreational ( n =12). Both groups completed a 4-min running bout at 13 and 17 km·h -1 , respectively, for the recreational and well-trained group, and a 5-jump plyometric test pre-post intervention. During the training program, participants completed low-intensity continuous sessions, high-intensity interval training sessions, and auxiliary strength training sessions. RE, measured as oxygen cost and energy cost, decreased by 6.15% (p=0.006) and 5.11% (p=0.043), respectively, in the well-trained group. In the recreational group, energy cost of running, respiratory exchange ratio, and leg stiffness decreased by 5.08% (p=0.035), 7.61% (p=0.003), and 10.59% (p=0.017), respectively, while ground contact time increased by 3.34% (p=0.012). The maximum height of the 5-jump plyometric test decreased by 4.55% (p=0.018) in the recreational group. We suggest that 8 weeks of regular endurance training leads to an improvement of ~5% in RE in recreational and well-trained runners with different physiological adaptations between groups and few changes in biomechanical and neuromuscular parameters only in recreational runners., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Thieme. All rights reserved.)

The dynamic complexity and individualization of running biomechanics has challenged the development of objective and comparative gait measures. Here, we present and explore several novel biomechanical metrics for running that are informed by a canonical inter-species gait template-the spring-mass model. The measures assess running mechanics systemically against the template via quantifying characteristics of a runner's kinetics relative to the energy-conserving elastic system-i.e., their "spring-mass similarity". Applying these metrics in a retrospective cohort investigation, we studied the overground kinetics of two heterogenous populations of runners in two footwear conditions: elite and recreational athletes in shod and barefoot conditions. Across all measures and within foot strike types, the elite runners exhibited mechanics that were more similar to those of the ideally elastic spring-mass template. The elite runners had more symmetric bounces, less discrepancy (i.e., greater coordination) between horizontal and vertical kinetic changes, and better fit to a spring-mass vertical ground reaction force time series. Barefoot running elicited greater kinetic coordination in the recreational runners. At a faster speed, the elites further improved their similarity to the template. Overall, the more economical elite group exhibited greater likeness to the linearly elastic, energy-conserving spring-mass system than their recreational counterparts. This study introduces novel biomechanical measures related to performance in distance running. More broadly, it provides new, approachable metrics for systemic quantification of gait biomechanics in runners across all demographics. These metrics may be applied to assess a runner's global biomechanical response to a variety of interventions, including training adaptations, rehabilitation programs, and footwear conditions., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Burns, Tam, Santos-Concejero, Tucker and Zernicke.)

Post-Activation Performance Enhancement (PAPE) has been commonly used as a strategy to improve acute force production, although its effects on performance to volitional failure are still unknown. The aim of this study was to analyse the influence of a PAPE protocol on bench press performance in a training set to volitional failure in trained individuals. Fourteen participants with at least two years of resistance training experience (age 24.57 ± 2.7 years; body mass 77.47 ± 12.2 kg; body height 174.21 ± 7.4 cm; medium grip bench press 1 repetition maximum (1RM): 101.6 ± 25.8 kg), of which 14 completed the control protocol and 12 completed the experimental protocol, took part in the study. After a standardised warm-up, participants completed three sessions: 1) a 1RM test for the medium grip bench press, 2) a control condition consisting of a set of the bench press to volitional failure with 80% 1RM (CON), and 3) an experimental condition consisting of a set of the bench press to volitional failure with 80% 1RM after a PAPE protocol (PAPE). The PAPE protocol consisted of a heavy set of one repetition with their 93% 1RM as the conditioning activity. Under the PAPE condition, participants performed significantly more repetitions than under the CON condition (p = 0.008, ES = 0.5, small effect), their last repetition was slower (p = 0.02, ES = 0.52, small effect) and presented a higher velocity loss (p = 0.004, ES = 0.75, moderate effect). These results suggest that a traditional PAPE protocol improves the number of repetitions performed to volitional failure., Competing Interests: The authors declare no conflict of interest., (Copyright: © Academy of Physical Education in Katowice.)

The aim of the present study was to analyse the role of exercises' resistance profile in regional hypertrophy. Thirty-eight healthy women completed a 9-week resistance training program consisting of either 4 sets of 12 repetitions to volitional failure of inclined bicep curls (INC group) or preacher curls (PREA group), three times per week. Pre- and post-intervention muscle thickness was measured using B-mode ultrasound imaging with a linear-array transducer. Scan acquisition sites were determined by measuring 50%, 60% and 70% of the distance between the posterior crest of the acromion and the olecranon. Statistical significance was set at p < 0.05. No region of the INC group grew when comparing pre- to post-intervention. The 70% region of the PREA group grew significantly (muscle thickness increased from 2.7 ± 0.43 cm to 2.94 ± 0.44 cm). We found no growth differences between regions when analysing per group (p = 0.274), region (p = 0.571) or group*region (p = 0.367). Our results show that the distal region of the arm grows in response to the preacher curl that places the highest amount of strain in the range of motion in which the arm muscles are more elongated., Competing Interests: The authors declare no conflict of interest., (Copyright: © Academy of Physical Education in Katowice.)

We analysed the effects of the Nike ZoomX Vaporfly (VPF) on long-interval training performance, kinematic parameters, running power and fatigue compared to a traditional running shoe. Twelve well-trained men (mean ± SD: 32.91 ± 7.50 years; 69.29 ± 7.55 kg and 172.73 ± 5.97 cm) performed two long-interval training sessions (5 × 1000 m with 90s recovery period) 7 days apart, with the VPF shoe or a traditional running shoe (CON) in random order. The countermovement jump (CMJ) height was measured before and after the training sessions and heart rate, spatiotemporal parameters, running power and leg stiffness was measured during training sessions. Running-related pain was assessed prior and post-24 h of each training session. Long-interval training performance improved 2.4% using the VPF shoe compared to CON ( p  = 0.009; ES = 0.482). Step length, contact time and leg stiffness were higher ( p  < 0.05; ES = 0.51, ES = 0.677, ES = 0.356) while flight time was lower ( p  < 0.001; ES = 0.756) when using VPF. Running power decreased in a similar way in both conditions throughout the training session. Vertical power was significantly higher in the VPF condition ( p  = 0.023, ES = 0.388). CMJ height decreased in both conditions after training (4.7 vs. 7.2%, for the VPF and control, respectively, p  < 0.001; ES = 0.573). Finally, the perceived muscle pain was influenced by the shoe model condition (chi-square 5.042, P  = 0.025). VPF shoes improved the long-interval training performance with similar running power, heart rate and neuromuscular fatigue, and reduced subjective perceived muscle pain compared to regular training shoes. Highlights VPF shoe may improve long-interval training performance in trained runners with the same running power and heart rate.Lower subjective perceived muscle pain is found with VPF compared to the regular training shoes.This type of footwear may be used in high-intensity training sessions aiming to increase the training volume at higher intensities with lower associated fatigue.

During the last years, post-activation performance enhancement (PAPE) has gained notorious popularity due to the capacity to improve the acute rate of force development (RFD) using different strategies with different muscle contraction regimes as conditioning stimuli. The aim of the present study was to analyse the role of a maximal isometric post-activation performance enhancement (PAPE) protocol in performance and its effects on the kinematics of the sticking region. Twenty-one trained participants (age 26.4 ± 5.4 years) underwent two experimental sessions: an experimental session consisting of a single set and a single repetition of the bench press at the 93% of 1RM (which is considered a traditional conditioning activity to induce PAPE) (TRAD) and an isometric experimental session (ISO) consisting of 15 maximal voluntary isometric contractions in the sticking region of the medium grip bench press lasting 1 s with a 1 s rest interval between contractions. Both TRAD and ISO experimental conditions improved performance from post0 to post4, post8, post12 and post16, but only the ISO condition improved performance from the start of the lift to the start of the sticking region from pre to post (p < 0.001), and only the ISO condition improved maximum (p = 0.005) and minimum (p = 0.025) peak velocities. The results of this study suggest that short duration maximal voluntary isometric contractions improve the velocity of the lift prior to the initiation of the sticking region, which ultimately improves the impulse and facilitates the lift., (Copyright: © Academy of Physical Education in Katowice.)

Advanced footwear technology (AFT) changed footwear design concepts by using a curved carbon fibre plate in combination with new, more compliant and resilient foams. The aim of this study was (1) to examine the individual effects of AFT on the evolution of the main road events and (2) to re-assess the impact of AFT on the world's top-100 performance in men's 10k, half-marathon and marathon events. Data from the top-100 men's 10k, half-marathon and marathon performances were collected between 2015 and 2019. The shoes used by the athletes were identified in 93.1% of the cases by publicly available photographs. Runners wearing AFT had an average performance of 1671 ± 22.28 s compared to 1685 ± 18.97 s of runners not using AFT in 10k (0.83%) ( p  < 0.001), 3589 ± 29.79 s compared to 3607 ± 30.49 s in half-marathon (0.50%) ( p  < 0.001) and 7563 ± 86.10 s compared to 7637 ± 72.51 s in the marathon (0.97%) ( p  < 0.001). Runners wearing AFTs were faster by ~1% in the main road events compared to non-users. Individual analysis showed that ~25% of the runners did not benefit from the use of this type of footwear. The results of this study suggest that AFT has a clear positive impact on running performance in main road events.

This study aimed to address the effects of increased longitudinal bending stiffness (LBS) on running economy (RE) and running biomechanics. A systematic search on four electronic databases (Pubmed, WOS, Medline and Scopus) was conducted on 26 May 2021. Twelve studies met the inclusion criteria and were included. Standardised mean difference with 95% confidence intervals (CI) between footwear with increased LBS vs . non-increased LBS conditions and effect sizes were calculated. To assess the potential effects of moderator variables (type and length plate, increased LBS, shoe mass and running speed) on the main outcome variable (i.e. RE), subgroup analyses were performed. Increased LBS improved RE (SMD = -0.43 [95% CI -0.58, -0.28], Z  = 5.60, p  < 0.001) compared to non-increased LBS. Significant increases of stride length (SMD = 0.29 [95% CI 0.10, 0.49], Z  = 2.93, p  = 0.003) and contact time (SMD = 0.17 [95% CI 0.03, 0.31], Z  = 2.32, p  = 0.02) were found when LBS was increased. RE improved to a greater degree at higher running speeds with footwear with increased LBS. RE improved 3.45% with curve plate compared to no-plate condition without improvements with flat plate shoes. When shoe mass was matched between footwear with increased LBS vs. non-increased LBS conditions, RE improved (3.15%). However, when shoe mass was not controlled (experimental condition with ∼35 grams extra), a significant small improvement was found. These RE improvements appear along with an increase of stride length and contact time. Shoe mass, type of plate (flat or curve) and running speed should be taken into consideration when designing a shoe aimed at improving long-distance running performance.

Resistance training is frequently performed with the goal of stimulating muscle hypertrophy. Due to the key roles motor unit recruitment and mechanical tension play to induce muscle growth, when programming, the manipulation of the training variables is oriented to provoke the correct stimulus. Although it is known that the nervous system is responsible for the control of motor units and active muscle force, muscle hypertrophy researchers and trainers tend to only focus on the adaptations of the musculotendinous unit and not in the nervous system behaviour. To better guide resistance exercise prescription for muscle hypertrophy and aiming to delve into the mechanisms that maximize this goal, this review provides evidence-based considerations for possible effects of neural behaviour on muscle growth when programming resistance training, and future neurophysiological measurement that should be tested when training to increase muscle mass. Combined information from the neural and muscular structures will allow to understand the exact adaptations of the muscle in response to a given input (neural drive to the muscle). Changes at different levels of the nervous system will affect the control of motor units and mechanical forces during resistance training, thus impacting the potential hypertrophic adaptations. Additionally, this article addresses how neural adaptations and fatigue accumulation that occur when resistance training may influence the hypertrophic response and propose neurophysiological assessments that may improve our understanding of resistance training variables that impact on muscular adaptations., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The main goal of this study was to compare responses to moderate and high training volumes aimed at inducing muscle hypertrophy. A literature search on 3 databases (Pubmed, Scopus and Chocrane Library) was conducted in January 2021. After analyzing 2083 resultant articles, studies were included if they met the following inclusion criteria: a) studies were randomized controlled trials (with the number of sets explicitly reported), b) interventions lasted at least six weeks, c) participants had a minimum of one year of resistance training experience, d) participants' age ranged from 18 to 35 years, e) studies reported direct measurements of muscle thickness and/or the cross-sectional area, and f) studies were published in peer-review journals. Seven studies met the inclusion criteria and were included in the qualitative analysis, whereas just six were included in the quantitative analysis. All participants were divided into three groups: "low" (<12 weekly sets), "moderate" (12-20 weekly sets) and "high" volume (>20 weekly sets). According to the results of this meta-analysis, there were no differences between moderate and high training volume responses for the quadriceps (p = 0.19) and the biceps brachii (p = 0.59). However, it appears that a high training volume is better to induce muscle mass gains in the triceps brachii (p = 0.01). According to the results of this review, a range of 12-20 weekly sets per muscle group may be an optimum standard recommendation for increasing muscle hypertrophy in young, trained men., (© 2022 Eneko Baz-Valle, Carlos Balsalobre-Fernández, Carlos Alix-Fages, Jordan Santos-Concejero, published by Sciendo.)

Purpose: Optimal training for endurance performance remains a debated topic. In this case study, the training of a world-class middle-/long-distance runner over a year's duration is presented., Methods: The training is analyzed via 2 methods to define training intensity distribution (TID) (1) by physiological zones and (2) by zones based on race pace. TID was analyzed over the full season, but also over the final 6, 12, and 26 weeks to allow for consideration of periodization/phases of season. The results of both methods are compared. Other training data measured include volume and number of sessions., Results: The average weekly volume for the athlete was 145.8 (24.8) km·wk-1. TID by physiological analysis was polarized for the last 6 weeks of the season but was pyramidal when analyzed over the final 12, 26, and 52 weeks of the season. TID by race-pace analysis was pyramidal across all time points. The athlete finished 12th in the final of the World Championship 5000-m and made the semifinal of the 1500-m. He was ranked in the top 16 in the world for 1500, 5000, and 10,000 m., Conclusion: The results of this study demonstrate a potential flaw with recent work suggesting polarized training as the most effective means to improve endurance performance. Here, different analysis methods produced 2 different types of TID. A polarized distribution was only seen when analyzed by physiological approach, and only during the last 6 weeks of a 52-week season. Longer-term prospective studies relating performance and physiological changes are suggested.

The NIKE Vaporfly shoe was introduced in May 2017 as part of the original #Breaking2 Project (an event aimed to run the first marathon under 2 h). This new advanced shoe technology (NAST) changed the footwear design conception. The aim of this study was (i) to analyse the effect of NAST in men's marathon performance, (ii) to analyse whether the changes in the environmental constraints (temperature and wind) and orography of the marathons, age and birthplace of the runners has changed from 2015 to 2019 and (iii) to analyse the impact of NAST on the historical 50 best performances. Data from top-100 men's marathon performances were collected in that timeframe. The shoes used by the athletes were identified (in 91.8% of the cases) by publicly available photographs. External and environmental conditions of each marathon and age and birthplace of the runners were also analysed. Marathon performances improved from 2017 onwards between 0.75 and 1.50% compared to 2015 and 2016 (p < 0.05). In addition, the improvement was greater in the upper deciles than in the lower ones (p < 0.001). Runners wearing NAST ran ~ 1% faster in marathon compared to runners that did not use it (p < 0.001). When conducting an individual analysis of athletes who ran with and without NAST, 72.5% of the athletes who completed a marathon wearing NAST improved their performance by 0.68% (p < 0.01). External and environmental conditions, age or birthplace of runners seems not to have influenced this performance improvement. NAST has had a clear impact on marathon performance unchanged in the environmental constraints (temperature and wind), orography, age, and birthplace of the runners but with differences between venues., (© 2021. The Author(s).)

There is emerging evidence suggesting that muscle growth is not homogeneous through the muscle. The aim of the present study was to analyse the role of exercise selection in regional hypertrophy. Two randomly allocated groups with equal training volume and intensity performed squats in the smith machine (SMTH group) or the leg extension exercise (LEG group). Growth in proximal, central and distal regions of the rectus femoris (RF) and vastus lateralis (VL) muscles, jump height and body composition were analysed. Results show that the three regions of RF grew significantly in the participants of the LEG group (p < 0.05), while only the central region of VL grew significantly in the SMTH group (p < 0.05). In summary, this study confirms that exercise selection plays a role in regional hypertrophy. Whilst there may be still other factors that determine how muscles grow, it seems that the chosen exercises may be responsible of the differences observed in this study.

Abstract: 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 (R2 ≥ 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., (Copyright © 2019 National Strength and Conditioning Association.)

This study aimed to analyse the training intensity distribution (TID) of a group of 7 world-class middle- and long-distance runners over 50 weeks using two different approaches to organise TID zones: (1) based on individual specific race pace and; (2) based on physiological parameters. Analysed training data included training volume, intensity and frequency. The average weekly volume for the group was 135.4 ± 29.4 km·week -1 . Training volumes for Z1, Z2 and Z3 were 88.5 ± 1.1%, 7.4 ± 0.8% and 4.1 ± 0.7% respectively for race-pace based approach, and 87.2 ± 1.2%, 6.1 ± 0.7% and 6.6 ± 0.9% respectively for the physiological approach. Differences were found between the approaches in Z2 (large effect, ES = 1.20) and Z3 (moderate effect, ES = 0.93). The approach based on race-pace zones produced pyramidal distributions in both middle- and long-distance runners across all phases of the season. The physiological approach produced polarised and pyramidal distributions depending of the phase of the season in the middle-distance runners, and pyramidal type TID across all phases of the season in the long-distance runners. The results of this study demonstrate that the training analysis in a world-class group of runners shows different TID when assessed relative to race pace versus to physiological zones. This highlights a potential deficiency in training analysis and prescription methods which do not make reference to specific performance. An approach which makes reference to both physiological and performance measures may allow for a more consistent and logical analysis.

This review aimed to determine the ideal combination of post activation potentiation (PAP) strategies for an improved strength performance. After analysing 202 articles, 15 studies met the inclusion criteria. The findings of this review suggest that a potentiation effect exists as long as a minimum intensity and enough rest are provided. Although intensities of 65% 1RM are sufficient to elicit a potentiation effect, higher effects can be achieved with 85 - 90% 1RM intensities. Similarly, we found that experienced athletes will benefit more from a higher volume bout (1-3 sets), as long as 7-8 minutes of rest are allowed to avoid fatigue., (© 2021 Arkaitz Garbisu-Hualde, Jordan Santos-Concejero, published by Sciendo.)

Abstract: Baz-Valle, E, Fontes-Villalba, M, and Santos-Concejero, J. Total number of sets as a training volume quantification method for muscle hypertrophy: A systematic review. J Strength Cond Res 35(3): 870-878, 2021-This review aimed to determine whether assessing the total number of sets is a valid method to quantify training volume in the context of hypertrophy training. A literature search on 2 databases (PubMed and Scopus) was conducted on May 18, 2018. After analyzing 2,585 resultant articles, studies were included if they met the following criteria: (a) studies were randomized controlled trials, (b) studies compared the total number of sets, repetition range, or training frequency, (c) interventions lasted at least 6 weeks, (d) subjects had a minimum of 1 year of resistance training experience, (e) subjects' age ranged from 18 to 35 years, (f) studies reported morphologic changes through direct or indirect assessment methods, (g) studies involved subjects with no known medical conditions, and (h) studies were published in peer-reviewed journals. Fourteen studies met the inclusion criteria. According to the results of this review, the total number of sets to failure, or near to, seems to be an adequate method to quantify training volume when the repetition range lies between 6 and 20+ if all the other variables are kept constant. This approach requires further development to assess whether specific numbers of sets are key to inducing optimal muscle gains., (Copyright © 2018 National Strength and Conditioning Association.)

Purpose: The aim of this study was to assess the effects of adding shoe mass on running economy (RE), gait characteristics, neuromuscular variables and performance in a group of trained runners., Methods: Eleven trained runners (6 men and 5 women) completed four evaluation sessions separated by at least 7 days. The first session consisted of a maximal incremental test where the second ventilatory threshold (VT 2 ) and the speed associated to the VO 2max (vVO 2max ) were calculated. In the next sessions, RE at 75, 85, and 95% of the VT 2 and the time to exhaustion (TTE) at vVO 2max were assessed in three different shoe mass conditions (control, +50 g and +100 g) in a randomized, counterbalanced crossover design. Biomechanical and neuromuscular variables, blood lactate and energy expenditure were measured during the TTE test., Results: RE worsened with the increment of shoe mass (Control vs. 100 g) at 85% (7.40%, 4.409 ± 0.29 and 4.735 ± 0.27 kJ⋅kg -1 ⋅km -1 , p = 0.021) and 95% (10.21%, 4.298 ± 0.24 and 4.737 ± 0.45 kJ⋅kg -1 ⋅km -1 , p = 0.005) of VT 2 . HR significantly increased with the addition of mass (50 g) at 75% of VT 2 ( p = 0.01) and at 75, 85, and 95% of VT 2 ( p = 0.035, 0.03, and 0.03, respectively) with the addition of 100 g. TTE was significantly longer (∼22%, ∼42 s, p = 0.002, ES = 0.149) in the Control condition vs. 100 g condition, but not between Control vs. 50 g (∼24 s, p = 0.094, ES = 0.068)., Conclusion: Overall, our findings suggest that adding 100 g per shoe impairs running economy and performance in trained runners without changes in gait characteristics or neuromuscular variables. These findings further support the use of light footwear to optimize running performance., (Copyright © 2020 Rodrigo-Carranza, González-Mohíno, Santos-Concejero and González-Ravé.)

Background: Due to the importance of energy efficiency and economy in endurance performance, it is important to know the influence of different paddling cadences on these variables in the stand-up paddleboarding (SUP). The purpose of this study was to determine the effect of paddling at different cadences on the energy efficiency, economy, and physiological variables of international SUP race competitors. Methods: Ten male paddlers (age 28.8 ± 11.0 years; height 175.4 ± 5.1 m; body mass 74.2 ± 9.4 kg) participating in international tests carried out two test sessions. In the first one, an incremental exercise test was conducted to assess maximal oxygen uptake and peak power output (PPO). On the second day, they underwent 3 trials of 8 min each at 75% of PPO reached in the first test session. Three cadences were carried out in different trials randomly assigned between 45-55 and 65 strokes-min -1 (spm). Heart rate (HR), blood lactate, perceived sense of exertion (RPE), gross efficiency, economy, and oxygen uptake (VO 2 ) were measured in the middle (4-min) and the end (8-min) of each trial. Results: Economy (45.3 ± 5.7 KJ·l -1 at 45 spm vs. 38.1 ± 5.3 KJ·l -1 at 65 spm; p = 0.010) and gross efficiency (13.4 ± 2.3% at 45 spm vs. 11.0 ± 1.6% at 65 spm; p = 0.012) was higher during de 45 spm condition than 65 spm in the 8-min. Respiratory exchange ratio (RER) presented a lower value at 4-min than at 8-min in 55 spm (4-min, 0.950 ± 0.065 vs. 8-min, 0.964 ± 0.053) and 65 spm cadences (4-min, 0.951 ± 0.030 vs. 8-min, 0.992 ± 0.047; p < 0.05). VO 2 , HR, lactate, and RPE were lower ( p < 0.05) at 45 spm (VO 2 , 34.4 ± 6.0 mL·kg -1 ·min -1 ; HR, 161.2 ± 16.4 beats·min -1 ; lactate, 3.5 ± 1.0 mmol·l -1 ; RPE, 6.0 ± 2.1) than at 55 spm (VO 2 , 38.6 ± 5.2 mL·kg -1 ·min -1 ; HR, 168.1 ± 15.1 beats·min -1 ; lactate, 4.2 ± 1.2 mmol·l -1 ; RPE, 6.9 ± 1.4) and 65 spm (VO 2 , 38.7 ± 5.9 mL·kg -1 ·min -1 ; HR, 170.7 ± 13.0 beats·min -1 ; 5.3 ± 1.8 mmol·l -1 ; RPE, 7.6 ± 1.4) at 8-min. Moreover, lactate and RPE at 65 spm was greater than 55 spm ( p < 0.05) at 8-min. Conclusion: International male SUP paddlers were most efficient and economical when paddling at 45 spm vs. 55 or 65 spm, confirmed by lower RPE values, which may likely translate to faster paddling speed and greater endurance.

This review aimed to analyse factors that limited performance in ultra-marathons and mountain ultra-marathons. A literature search in one database (PubMed) was conducted in February 2019. Quality of information of the articles was evaluated using the Oxford´s level of evidence and the Physiotherapy Evidence Database (PEDro) scale. The search strategy yielded 111 total citations from which 23 met the inclusion criteria. Twenty one of the 23 included studies had a level of evidence 2b (individual cohort study), while the 2 remaining studies had a level of evidence of 5 (expert opinion). Also, the mean score in the PEDro scale was 3.65 ± 1.61, with values ranging from 0 to 7. Participants were characterised as experienced or well-trained athletes in all of the studies. The total number of participants was 1002 (893 men, 86 women and 23 unknown). The findings of this review suggest that fatigue in ultra-endurance events is a multifactorial phenomenon that includes physiological, neuromuscular, biomechanical and cognitive factors. Improved exercise performance during ultra-endurance events seems to be related to higher VO 2max values and maximal aerobic speed (especially during submaximal efforts sustained over a long time), lower oxygen cost of transport and greater running experience., (© 2020 Arkaitz Garbisu-Hualde, Jordan Santos-Concejero, published by Sciendo.)

Background: Oxygen cost of running is largely influenced by endurance training strategies, including interval and continuous training. However, which training method better reduces the oxygen cost remains unknown., Objective: This study aimed to systematically review the scientific literature and performs a meta-analysis to address the effects of different endurance training modalities on the oxygen cost of running., Methods: A literature search on 3 databases (MEDLINE, SPORTDiscus and Web of Science) was conducted on February 28, 2019. After analysing 8028 resultant articles, studies were included if they met the following inclusion criteria: (a) studies were randomised controlled trials, (b) studies included trained runners without previous injuries (c) interventions lasted at least 6 weeks, with participants allocated to Interval (INT) or Continuous (CON) groups, and (d) oxygen cost was assessed pre- and post-training intervention. Six studies (seven trials) met the inclusion criteria and were included in the meta-analysis. This resulted in 295 participants (n = 200 INT; n = 95 CON training method). Standardised mean difference with 95% confidence intervals (CI) between INT and CON conditions and effect sizes were calculated. To assess the potential effects of moderator variables (such as, age, VO 2max of participants, number of weeks of intervention) on main outcome (oxygen cost of running), subgroup analyses were performed., Results: Comparing changes from pre- to post-intervention, oxygen cost improved to a greater extent in CON when compared to INT interventions (0.28 [95% CI 0.01, 0.54], Z = 2.05, p = 0.04, I 2  = 30%). Oxygen cost improvements were larger in participants with higher VO 2max (≥ 52.3 ml kg -1  min -1 ) (0.39 [95% CI 0.06, 0.72], Z = 2.34, p = 0.02), and in programs greater or equal to 8 weeks (0.35 [95% CI 0.03, 0.67], Z = 2.13, p = 0.03). When the total volume per week of INT was ≥ 23.2 min, there was a significant improvement favorable to CON (0.34 [95% CI 0.01, 0.61], Z = 2.02, p = 0.04)., Conclusion: Continuous training seems, overall, a better strategy than interval training to reduce the oxygen cost in recreational endurance runners. However, oxygen cost reductions are influenced by several variables including the duration of the program, runners' aerobic capacity, the intervals duration and the volume of interval training per week. Practitioners and coaches should construct training programs that include both endurance training methods shown to be effective in reducing the oxygen cost of running.

Background: The objective of the present study was to compare the effects of a traditional resistance training program (fixed exercises and repetition ranges) to a resistance training program where exercises and repetition ranges were randomized on a session-by-session basis on markers of muscular adaptations and intrinsic motivation., Methods: Twenty-one resistance trained men were randomized to perform an 8-week resistance training program using either a fixed exercise selection (CON) or having exercises randomly varied each session via a computerized app. Both groups performed 3 sets of 6 exercises, with training carried out 4 times per week., Results: Both conditions promoted large, statistically significant increases in the bench press and back-squat 1 repetition maximum without differences between groups. Muscle thickness (MT) measures for the individual quadriceps showed large, statistically significant increases in of the vastus lateralis and rectus femoris for both conditions, with no observed between-group differences. Although no between-group in MT were noted for the vastus intermedius, only the CON displayed significant increases from baseline. Participants in EXP showed a significant, moderate improvement in the intrinsic motivation to training, while participants in the CON group presented non-significant decreases in this variable., Conclusions: Varying exercise selection had a positive effect on enhancing motivation to train in resistance-trained men, while eliciting similar improvements in muscular adaptations., Competing Interests: The authors have declared that no competing interests exist

The main goal of this study was to analyse the pacing strategies displayed by the winners of the six World Marathon Majors in order to determine which race offers the greatest potential for future world record attempts. For data analysis, the total distance of the marathon was divided into eight sections of 5 km and a final section of 2.195 km, and time needed to complete each section was calculated in seconds. When we analyzed the mean winning time in the last 13 editions of each of the World Marathon Majors, we observed differences between New York and London (ES = 1.46, moderate effect, p = 0.0030), New York and Berlin (ES = 0.95, small effect, p = 0.0001), London and Boston (ES = 0.08, small effect, p = 0.0001), Boston and Berlin (ES = 0.10, small effect, p = 0.0001), Boston and Chicago (ES = 0.16, small effect, p = 0.0361), Berlin and Tokyo (ES = 0.20, small effect, p = 0.0034), Berlin and Chicago (ES = 0.27, small effect, p = 0.0162). This study shows that Berlin and London are likely candidates for future world record attempts, whilst such a performance is unlikely in New York or Boston., (Copyright © 2019 Díaz, Renfree, Fernández-Ozcorta, Torres and Santos-Concejero.)