The relationship between internal and external loads as a tool to monitor physical fitness status of team sport athletes: a systematic review

The efficiency index (Effindex) combines internal and external loads, and it has been considered a promising tool to evaluate physical fitness status. However, its real applicability and limitations have not been elucidated yet. To examine and discuss the findings from studies that used Effindex as a tool for the evaluation of physical fitness status in team sports. A systematic search was performed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). The databases conferred were PubMed, Scopus, Web of Science, SPORTDiscus, MEDLINE and CINAHL. The articles selected were published up to March 2021. Fourteen articles were included after meeting the inclusion criteria. A wide variety of combinations of external and internal loading parameters to calculate Effindex were found. The pooled sample included 349 male participants (23 ± 3years). Fifty-nine percent of the sample were soccer players, 20% rugby players, 10% Australian football players, 7% hurling players, and 4% basketball players. Most Effindex calculations used total distance (TD) divided by heart rate derived parameters. However, recent studies have suggested the use of accelerations as the external load parameter. Effindex is a simple and powerful tool for the evaluation of physical fitness status in team sports athletes. The disparity of external and internal loading parameters used to calculate Effindex may affect its sensitivity to detect changes in fitness status in different team sport settings. More studies with indoor team sports and female athletes are warranted

Eight steps’ paradigm shift in men’s 110 metres hurdles: an 89 years retrospective study

Men’s 110 metres hurdles is one of the oldest disciplines in the Olympic Games and yet scarce anecdotal reports are found to pinpoint technical elements indicators of success. The approach technique to the hurdles has been raised by coaches as a potential element of success however it seems that the approach strategies undertaken to the first hurdle have not been investigated to the current date. Therefore, this study aimed to examine the employment of the seven and eight steps strategy until the first hurdle in the 110 m discipline among the Olympic Games and World Championships in Athletics’ finalists. Public domain videos of the events in the period between 1924 and 2013 were assessed. An international level sprint and hurdles’ coach, using the Dartfish software, assessed the number of steps taken until the first hurdle. A left-tailed one sample sign test showed that although the seven steps strategy adoption seems to have begun in 1960 it was only in 2011 that it was considered a dominant tactic. Due to determination of factors that influence the choice of strategy or their respective influence on performance falling outside the scope of this study, future research is needed in this area. Notwithstanding, the success by the hurdlers that adopt the seven steps strategy, evidenced by the number of medals won, allowed to pinpoint the approach strategy to the first hurdle as a potential performance variable to be investigated

The validity and reliability of the “My Jump App” for measuring jump height of the elderly

[EN] Background: The ability to jump has been related to muscle strength and power, speed and amplitude of the lower limbs movements, and specifically for the elderly, the vertical jump has been shown to be a good predictor of functional capacity and risk of falling. The use of a mobile application (App) which can measure the vertical jump (i.e., iPhone App My Jump) has recently emerged as a simple, cheap and very practical tool for evaluation of jump ability. However, the validity of this tool for the elderly population has not been tested yet. The elderly usually perform very low jumps and therefore the signal-to-noise ratio may compromise the validity and reliability of this method. Thus, the aim of the current study was to verify the validity and reliability of the iPhone App “My Jump” for the evaluation of countermovement jump (CMJ) height within an elderly population. Methods: After familiarization, 41 participants performed three CMJs assessed via a contact mat and the My Jump App. The intraclass correlation coefficient (ICC) was used to verify the relative reliability, while the coefficient of variation (CV%) and the typical error of measurement (TEM) were used to verify the absolute reliability. Pearson’s correlation coefficient was used to verify the strength of the relationship between methods (i.e., concurrent validity), a Bland–Altman plot to show their agreement, and the Student’s t-test to identify systematic bias between them. For reliability analyses, all jumps were considered (i.e., 123). All jumps (i.e., 123), the average height of each attempt (i.e., 41), and the highest jump, were considered for validity analyses. Results: The CMJ height of the highest jump was 10.78 ± 5.23 cm with contact mat, and 10.87 ± 5.32 with My Jump App, with an identified systematic bias of 0.096 cm (P = 0.007). There was a nearly perfect correlation between methods (r = 0.999; P = 0.000, in all cases) with a very good agreement observed (0.3255 to -0.5177 cm, 0.2797 to -0.5594 cm, and 0.3466 to -0.6264 cm, for highest jump height, average jump height, and all jump heights, respectively). The ICC of the My Jump App was 0.948, the TEM was 1.150 cm, and the CV was 10.10%. Conclusion: Our results suggest that the My Jump App is a valid and reliable tool compared to the contact mat for evaluating vertical jump performance in the elderly.André Ricarte Medeiros (UC17351170) received a PROSUP scholarship grant from CAPES. Daniel A. Boullosa received a productivity grant from CNPq (305131/2015-0)We would like to thank Dr. David Behm for his advice and the English revision of the manuscript

Exercise-associated muscle cramps and creatine kinase responses after workload spikes in a professional soccer player: a case study

Purpose. Exercise-associated muscle cramps (EAMC) are characterized by intense pain and involuntary contractions of a single muscle or muscle group. While EAMCs may occur during and after exercise, their precise aetiology remains unknown. However, there are some potential risk factors, as the workload of physical training previously performed. The purpose of this case report was to evaluate the acute:chronic workload ratio (ACWR) and creatine kinase (CK) concentrations in a professional soccer player to verify the potential influence of recent training history on an extreme EAMC episode and subsequent muscle damage. Methods. A 21-year-old professional soccer player (body fat: 6.5%; body mass: 76 kg; height: 1.76 m) who experienced an extreme EAMC episode after the end of an official soccer match was monitored with session rating of perceived exertion before and after the EAMC episode and with post-match CK concentrations. Results. ACWR revealed several spikes on the days before the match, with the highest one observed on the match day. The CK concentrations recorded 35 and 53 hours after the EAMC episode were 262% and 182% higher, respectively, than the maximal CK concentrations recorded during the season (703 U/l). Conclusions. This case report illustrates, for the first time, how workload spikes, monitored with ACWR, preceded an extreme EAMC episode that was followed by an exacerbated muscle damage response. Some insights are provided in this case report for practitioners working in professional soccer to help them better manage similar cases

Análise do somatotipo e condicionamento físico entre atletas de futebol de campo sub-20

The objective of this study was to compare the Somatotype, Explosive force, Speed, Anaerobic and Aerobic resistance between semi-professional and professional athletes of sub-20 category. For that, 20 athletes were separated into two groups and were respectively carried through the following tests with its variables: Somatotype; Vertical jump without countermovement; Test of race speed of 30 meters, Running-based anaerobic sprint test and Yo-yo intermittent recovery test. Both groups had assumed somatotype predominance of “Balanced Mesomorphy”, and had demonstrated the importance of the body mass as a variable to be related in the obtain of the Explosive force. Therefore, we consider somatotype and physical capacity contributing factors for the best performance of the functions technician and tactics of the players.O objetivo deste estudo foi comparar o Somatotipo, Força Explosiva, Velocidade, Resistência Anaeróbica e Aeróbica entre atletas Semiprofissionais e Profissionais da categoria Sub-20. Para tanto, 20 atletas separados nos 2 grupos realizaram os seguintes testes com suas variáveis: Somatotipia (Endomorfia, Mesomorfia e Ectomorfia); Salto Vertical sem Contra-Movimento; Teste de Corrida de Velocidade de 30 metros; Running-based Anaerobic Sprint Test e Yo-yo Intermitent Recovery test. Ambos os grupos assumiram predominância somatotípica de “Mesomorfo Equilibrado”, e demonstraram a importância da Massa Corporal como uma variável a ser relacionada na obtenção da Força Explosiva. Assim, consideramos o Somatotipo e o Condicionamento Físico contribuintes para o melhor desempenho das funções técnico e táticas dos jogadores

a living systematic review

Background: Hamstrings injuries are common in sports and the reinjury risk is high. Despite the extensive literature on hamstrings injuries, the efectiveness of the diferent conservative (i.e., non-surgical) interventions (i.e., modalities and doses) for the rehabilitation of athletes with acute hamstrings injuries is unclear. Objective: We aimed to compare the efects of diferent conservative interventions in time to return to sport (TRTS) and/or time to return to full training (TRFT) and reinjury-related outcomes after acute hamstrings injuries in athletes. Data Sources: We searched CINAHL, Cochrane Library, EMBASE, PubMed, Scopus, SPORTDiscus, and Web of Science databases up to 1 January, 2022, complemented with manual searches, prospective citation tracking, and consultation of external experts. Eligibility Criteria: the eligibility criteria were multi-arm studies (randomized and non-randomized) that compared conservative treatments of acute hamstrings injuries in athletes. Data Analysis: We summarized the characteristics of included studies and conservative interventions and analyzed data for main outcomes (TRTS, TRFT, and rate of reinjuries). The risk of bias was judged using the Cochrane tools. Quality and completeness of reporting of therapeutic exercise programs were appraised with the i-CONTENT tool and the certainty of evidence was judged using the GRADE framework. TRTS and TRFT were analyzed using mean diferences and the risk of reinjury with relative risks. Results Fourteen studies (12 randomized and two non-randomized) comprising 730 athletes (mostly men with ages between 14 and 49 years) from diferent sports were included. Nine randomized studies were judged at high risk and three at low risk of bias, and the two non-randomized studies were judged at critical risk of bias. Seven randomized studies compared exercise-based interventions (e.g., L-protocol vs C-protocol), one randomized study compared the use of low-level laser therapy, and three randomized and two non-randomized studies compared injections of platelet-rich plasma to placebo or no injection. These low-level laser therapy and platelet-rich plasma studies complemented their interventions with an exercise program. Only three studies were judged at low overall risk of inefectiveness (i-CONTENT). No single intervention or combination of interventions proved superior in achieving a faster TRTS/TRFT or reducing the risk of reinjury. Only eccentric lengthening exercises showed limited evidence in allowing a shorter TRFT. The platelet-rich plasma treatment did not consistently reduce the TRFT or have any efect on the risk of new hamstrings injuries. The certainty of evidence was very low for all outcomes and comparisons. Conclusions: Available evidence precludes the prioritization of a particular exercise-based intervention for athletes with acute hamstrings injuries, as diferent exercise-based interventions showed comparable efects on TRTS/TRFT and the risk of reinjuries. Available evidence also does not support the use of platelet-rich plasma or low-level laser therapy in clinical practice. The currently available literature is limited because of the risk of bias, risk of inefectiveness of exercise protocols (as assessed with the i-CONTENT), and the lack of comparability across existing studies. Clinical Trial Registration PROSPERO CRD42021268499 and OSF (https://osf.io/3k4u2/).9513-E3E4-C5C9 | Sílvia Fernanda Rocha RodriguesN/

Providing Explainable Race-Time Predictions and Training Plan Recommendations to Marathon Runners

The Fourteenth ACM Conference on Recommender Systems (RecSys '20), Rio de Janeiro (held online due to coronavirus outbreak), 22- 26 September 2020Millions of people participate in marathon events every year, typically devoting at least 12-16 weeks to building their endurance and fitness so that they can safely complete these gruelling 42.2km races. Most runners follow a training plan that is tailored to their expected finish-time (e.g. sub-4 hours or 4-5 hours), and these plans will prescribe a complex mixture of training sessions to help them achieve these times. However, such plans cannot adapt to the individual needs (fitness levels, changing goals, personal preferences) of runners, providing only broad training guidance rather than more personalised support. The development of wearable sensors and mobile fitness applications facilitates the collection of a large amount of training data from runners. In this paper, we propose a recommender system that utilizes such training data to deliver more personalised training advice to runners, using ideas from case-based reasoning to reuse and adapt the training habits of similar runners. Explainability plays a significant role in this type of system, and we also describe how the predictions and recommendation advice can be presented to runners. An initial off-line evaluation is presented based on a large-scale, real-world dataset.Science Foundation IrelandInsight Research Centre2020-11-27 JG: Broken PDF replace

Football scout analysis models (based in the 2013/2014 Champions League)

Conquistar as primeiras posições em competições de futebol é apenas para alguns times. Assim, um melhor entendimento do jogo se torna crucial mediante essa competitividade. O objetivo do presente estudo foi determinar variáveis de scout que melhor descrevem as características técnicas e táticas dos times que participaram de Liga dos Campeões na temporada 2013/2014. Todos os jogos acessíveis das fases de classifi cação e das fi nais da Liga dos Campeões da UEFA (32 times e 126 partidas) foram analisados usando o scout dos dados disponíveis para domínio publico. As variáveis analisadas foram gols marcados, saldo de gols, fi nalizações totais, fi nalizações a gol, desarmes, escanteios, tiros de meta, passes certos, passes errados, número de faltas cometidas e posse de bola. As variáveis mais relevantes para descrever uma partida, apontadas pela analise de regressão múltipla foram as fi nalizações totais (r²=0.815), posse de bola (r²=0.748), passes certos (r²=0.742) e gols marcados (r²=0.699). O presente estudo foi capaz de mostrar como as informações obtidas pelo scout podem ser agrupadas para fácil aplicação pelos treinadores.First places in major football competitions are no longer a few teams’ achievement. A better understanding of the game becomes crucial with this highly competitive background. Our purpose was to determine scout variables that best describe the technical and tactical characteristics of the 2013/2014 Champions League’s participating teams. All UEFA Champions League’s qualifying phases and play-offs matches (32 teams in 126 matches) were analyzed using scout public domain data. The analyzed variables were goals scored, goals difference, total attempts, attempts on target, disarms, corners, offside, passes completed, passes uncompleted, fouls committed and ball possession. A best subsets multiple regression analysis reveal that total attempts (r²=0.815), ball possession (r²=0.748), passes completed (r²=0.742) and scored goals (r²=0.699) are the most relevant variables to describe the match. The present study was able to show how scout information can be reduced to the coach easily application. Statistics, Soccer, UEFA, Competitions

The validity and reliability of the “My Jump App” for measuring jump height of the elderly

Background The ability to jump has been related to muscle strength and power, speed and amplitude of the lower limbs movements, and specifically for the elderly, the vertical jump has been shown to be a good predictor of functional capacity and risk of falling. The use of a mobile application (App) which can measure the vertical jump (i.e., iPhone App My Jump) has recently emerged as a simple, cheap and very practical tool for evaluation of jump ability. However, the validity of this tool for the elderly population has not been tested yet. The elderly usually perform very low jumps and therefore the signal-to-noise ratio may compromise the validity and reliability of this method. Thus, the aim of the current study was to verify the validity and reliability of the iPhone App “My Jump” for the evaluation of countermovement jump (CMJ) height within an elderly population. Methods After familiarization, 41 participants performed three CMJs assessed via a contact mat and the My Jump App. The intraclass correlation coefficient (ICC) was used to verify the relative reliability, while the coefficient of variation (CV%) and the typical error of measurement (TEM) were used to verify the absolute reliability. Pearson’s correlation coefficient was used to verify the strength of the relationship between methods (i.e., concurrent validity), a Bland–Altman plot to show their agreement, and the Student’s t-test to identify systematic bias between them. For reliability analyses, all jumps were considered (i.e., 123). All jumps (i.e., 123), the average height of each attempt (i.e., 41), and the highest jump, were considered for validity analyses. Results The CMJ height of the highest jump was 10.78 ± 5.23 cm with contact mat, and 10.87 ± 5.32 with My Jump App, with an identified systematic bias of 0.096 cm (P = 0.007). There was a nearly perfect correlation between methods (r = 0.999; P = 0.000, in all cases) with a very good agreement observed (0.3255 to −0.5177 cm, 0.2797 to −0.5594 cm, and 0.3466 to −0.6264 cm, for highest jump height, average jump height, and all jump heights, respectively). The ICC of the My Jump App was 0.948, the TEM was 1.150 cm, and the CV was 10.10%. Conclusion Our results suggest that the My Jump App is a valid and reliable tool compared to the contact mat for evaluating vertical jump performance in the elderly. Therefore, it allows a simple and practical assessment of lower limbs’ power in this population. For the elderly, as well as for other populations with low jumping heights, the highest jump height and the average jump height could be used indistinctly

Do you Play or Do you Train? Insights From Individual Sports for Training Load and Injury Risk Management in Team Sports Based on Individualization

[EN] The understanding of the potential causes of musculoskeletal injuries in any competitive sport needs to address their multifactorial nature, which results from complex associations among different external conditions and modifiable and non-modifiable intrinsic risk factors (Drew and Purdam, 2016; Kalkhoven et al., 2020a). In this context, the cause of any non-contact injury merely results from a sum of loads generating a force that exceeds the limit supported by the respective biological tissue (Zernicke and Whiting, 2008). Consequently, it has been suggested that a poor load management is a major risk factor for injury in sport settings (Gabbett, 2016). One novel monitoring tool for injury risk management is the acute: chronic workload ratio (ACWR). The ACWR is currently in the spot light of sport sciences (Griffin et al., 2020; Maupin et al., 2020). While some emerging evidence suggests that it is a valid method to identify an increased injury risk (Andrade et al., 2020), other authors have pointed out its methodological limitations and even questioned its validity (Impellizzeri et al., 2020; Wang et al., 2020). Proponents of the ACWR approach argue that athletes are at greater risk of sustaining a time-loss injury when the ACWR is higher relative to a lower or moderate ACWR (Andrade et al., 2020). In other words, the ACWR helps to identify critical windows in terms of elevated injury risk based on imbalanced training loading as for example sudden spike loads (Bowen et al., 2020)