Quantifying the Peak Physical Match-Play Demands of Professional Soccer Substitutes Following Pitch-Entry: Assessing Contextual Influences.

Purpose: To quantify the peak post-pitch-entry physical responses of soccer substitutes while assessing contextual influences. Peak responses may be important performance indicators for substitutes introduced to provide a physical impact. Method: Thirty-three professional substitutes wore Microelectromechanical Systems during 44 matches (4 ± 3 observations·player-1). Post-pitch-entry relative peak values for total and high-speed (> 5.5 m·s-1) distances, average acceleration, and PlayerLoad™ were calculated using rolling averages over 60-s to 600-s. Linear mixed models assessed contextual influences (position, substitution timing, scoreline, and location). Results: Substitutes introduced during the final ~15 min of match-play covered less high-speed distance than first-half substitutes (~2.8-3.1 m·min-1) over 480-s to 600-s epochs, and less than 60:00-74:59 min substitutes (~1.7-1.8 m·min-1) during 540-s and 600-s epochs. Average acceleration during all except 180-s epochs was lower for 75:00+ min substitutes compared with first-half replacements (~0.27-0.43 m·s-2), and lower than 60:00-74:59 min substitutes during 60-s (~0.13 m·s-2). Substitutes introduced when their team was winning recorded greater distances over 120-s to 600-s (~6.2-7.7 m·min-1), and higher PlayerLoad™ values during 120-s, 180-s, 300-s, and 480-s epochs (~2.7-3.6 arbitrary units·min-1), compared with when scores were level at pitch-entry. Irrespective of substitution timing, substitute midfielders exceeded the total distance of substitute attackers (~5.9-16.2 m·min-1) for all except 360-s and 600-s epochs, and defenders (~13.3-26.7 m·min-1) during epochs < 300-s. Conclusions: This study provides benchmark data for practitioners tailoring training and recovery protocols, particularly "top-up" conditioning, to the competitive demands of soccer substitutes. Knowing how contextual factors influence substitutes' peak match-play responses may help managers/coaches assess the efficacy of substitution strategies.

Body temperature and physical performance responses are not maintained at the time of pitch-entry when typical substitute-specific match-day practices are adopted before simulated soccer match-play.

OBJECTIVES: To profile performance and physiological responses to typical patterns of match-day activity for second-half soccer substitutes. DESIGN: Descriptive. METHODS: Following a warm-up, 13 male team sports players underwent ∼85min of rest, punctuated with five min rewarm-ups at ∼25, ∼50, and ∼70min, before ∼30min of simulated soccer match-play. Countermovement jump performance (jump height, peak power output), alongside 15m sprints, were assessed post-warm-up, and pre- and post-simulated match-play. Core temperature, heart rate, ratings of perceived exertion, and blood glucose and lactate concentrations were measured throughout. RESULTS: Warm-up-induced core temperature elevations (∼2.3%, +0.85°C; p<0.001) were maintained until after the first rewarm-up. Thereafter, core temperature was reduced from post-warm-up values until pre-simulated match-play (∼1.6%, -0.60°C; p<0.001), where values were similar to pre-warm-up (37.07±0.24°C, p=0.981). Simulated match-play increased core temperature progressively (p≤0.05) but values remained lower than post-warm-up (∼5min; p=0.002) until ∼10min into exercise. From post-warm-up to pre-simulated match-play, sprint times (∼3.9%, +0.10s, p=0.003), jump height (∼9.4%, -3.1cm; p=0.017), and peak power output (∼7.2%, -296W; p<0.001) worsened. Despite increased ratings of perceived exertion and elevated blood lactate concentrations (p≤0.05), sprint times were maintained throughout exercise, whereas peak power increased (∼7.8%, +294W; p=0.006) pre- to post-exercise. CONCLUSIONS: At the point of simulated pitch-entry, body temperature and physical performance responses were not maintained from warm-up cessation despite typical substitute-specific match-day practices being employed in thermoneutral conditions. Evidence of performance-limiting fatigue was absent during ∼30min of simulated match-play. These data question the efficacy of practices typically implemented by substitutes before pitch-entry.

Profiling the Post-match Top-up Conditioning Practices of Professional Soccer Substitutes: An Analysis of Contextual Influences.

Hills, SP, Barrett, S, Busby, M, Kilduff, LP, Barwood, MJ, Radcliffe, JN, Cooke, CB, and Russell, M. Profiling the post-match top-up conditioning practices of professional soccer substitutes: An analysis of contextual influences. J Strength Cond Res 34(10): 2805-2814, 2020-Soccer practitioners implement "top-up" conditioning sessions to compensate for substitutes' limited match-play exposure. Although perceived to be valuable for reducing injury risk and augmenting positive physical adaptations, little research has considered the demands of post-match top-up training. To quantify post-match top-up responses, 31 professional soccer players wore 10 Hz microelectromechanical systems after 37 matches whereby they were selected in the match-day squad as substitutes (184 observations; 6 ± 5 observations·player). Linear mixed models and effect sizes (ES) assessed the influence of contextual factors on 23 physical performance variables. Top-ups lasted 17.13 ± 7.44 minutes, eliciting total and high-speed distances of 1.7 ± 6.2 km and 0.4 ± 1.7 km, respectively. Each contextual factor (i.e., position, substitution timing, match location, result, time of day, stage of the season, and fixture density) influenced at least 4 of the dependent variables profiled (p ≤ 0.05). Top-up duration; total, moderate-speed, and low-speed distance; and the number of repeated high-intensity efforts were greater for unused vs. used substitutes (ES: 0.38-0.73, small to moderate). Relative to away matches, home top-ups elicited heightened total, low-speed, and high-speed distances, alongside more moderate-speed accelerations and decelerations, and repeated high-intensity efforts (ES: 0.25-0.89, small to moderate). Although absolute and relative running distances were generally the highest when the fixture density was low, the greatest acceleration and deceleration demands were observed during the most congested fixture periods. Late-season top-ups typically elicited lower absolute physical responses than early and mid-season sessions. These data provide important information for practitioners when considering the aims and design of substitute top-up conditioning sessions, particularly with reference to contextual influences.

Modifying the pre-pitch entry practices of professional soccer substitutes may contribute towards improved movement-related performance indicators on match-day: A case study.

Modifying a soccer substitute's pre-pitch-entry activities may represent an opportunity to maximise physical performance and minimise injury-risk following match-introduction. Using a professional team that has previously participated in substitute profiling research, this follow-up case study investigated the effects of a modified match-day protocol that included substitutes; 1) performing a new pre-match warm-up alongside members of the starting team (as opposed to a separate substitute-only warm-up), 2) participating in a staff-led half-time rewarm-up (as opposed to player-led half-time activities), and 3) receiving ongoing education focusing on the efficacy of (re)warm-up activities. English Championship substitutes (n = 15) were monitored using Micro-electromechanical Systems during 13 matches incorporating the modified practices (35 observations). On an individual player basis, data were organised into bouts of warm-up activity (pre-pitch-entry) and five min epochs of match-play (post-pitch-entry). Linear mixed modelling assessed the influence of 'bout' and 'epoch', position, and scoreline. Substitutes performed 3±1 rewarm-up bouts∙player-1∙match-1 between kick-off and pitch-entry, which were shorter (-17.2 to -27.1 min) and elicited less distance (-696 to -1257 m) than the pre-match warm-up (p≤0.001). Compared with previous data, heightened absolute movement responses were observed during the pre-match and staff-led half-time (re)warm-ups, alongside greater relative distances covered during player-led activities performed between kick-off and pitch-entry. Whilst less distance (-10%) was covered during the second versus first five min period following match-introduction, values remained higher than previously reported. Between pitch-entry and the end of the match, the scoreline improved and worsened following 26% and 11% of substitutions, respectively; a favourable record compared with existing observations. Acknowledging the likely contribution from external factors, this case study reports heightened movement profiles and improved match scorelines when pre-pitch-entry practices were modified. Practitioners should note the potential influence of match-day activities on the physical responses of soccer substitutes and, if deemed necessary, consider adapting their pre-pitch-entry routines accordingly.

Practitioner perceptions regarding the practices of soccer substitutes.

Despite empirical observations suggesting that practitioners value the use of substitutions during soccer match-play, limited research has sought to substantiate such claims. This study used online surveys to assess the perceptions of practitioners within professional soccer about the use and practices of substitutes. Thirty-three practitioners completed one of two surveys (each requiring both open and closed questions to be answered), depending upon whether their primary role related mostly to tactical ('tactical practitioners'; n = 7) or physical ('physical practitioners'; n = 26) aspects of player/team management. Thematic content analysis of responses identified four higher-order themes: 'impact of substitutions', 'planning and communication', 'player preparation and recovery' and 'regulations'. Eighty-five percent of practitioners believed that substitutes are important in determining success during soccer match-play, with the primary justification being the perceived ability of such players to provide a physical and/or tactical impact. However, contextual factors such as the match situation, timing of introduction, and players undergoing adequate pre-pitch-entry preparation, may be important for realising such aims. Although many practitioners believed that there was a need for substitutes to engage in bespoke non-match-day preparations and recovery strategies that differ from starting players, logistical considerations, such as scarcity of resources, often limit their scope. Notwithstanding, 96% of respondents indicated that substitutes frequently perform extra conditioning sessions to account for deficits in high-speed running loads compared with players exposed to a longer period of match-play. Substitutes' pre-match warm-ups are typically led by team staff, however practitioners reported providing varying levels of input with regards to the practices adopted between kick-off and pitch-entry. Uncertainty exists as to the efficacy of current pre-pitch-entry practices, and 100% of practitioners highlighted 'preparatory strategies' as at least a 'moderately important' direction for future research. This study presents novel insights and highlights areas that are considered future research priorities amongst those working in the field.

A match-day analysis of the movement profiles of substitutes from a professional soccer club before and after pitch-entry.

Whilst the movement demands of players completing a whole soccer match have been well-documented, comparable information relating to substitutes is sparse. Therefore, this study profiled the match-day physical activities performed by soccer substitutes, focusing separately on the pre and post pitch-entry periods. Seventeen English Championship soccer players were monitored using 10 Hz Micromechanical Electrical Systems (MEMS) devices during 13 matches in which they participated as substitutes (35 observations). Twenty physical variables were examined and data were organised by bouts of warm-up activity (pre pitch-entry), and five min epochs of match-play (post pitch-entry). Linear mixed modelling assessed the influence of time (i.e., 'bout' and 'epoch'), playing position, and match scoreline. Substitutes performed 3±1 rewarm-up bouts∙player-1∙match-1. Compared to the initial warm-up, each rewarm-up was shorter (-19.7 to -22.9 min) and elicited less distance (-606 to -741 m), whilst relative total distances were higher (+26 to +69 m∙min-1). Relative total (+13.4 m∙min-1) and high-speed (+0.4 m∙min-1) distances covered during rewarm-ups increased (p <0.001) with proximity to pitch-entry. Players covered more (+3.2 m; p = 0.047) high-speed distance per rewarm-up when the assessed team was losing compared with when winning at the time of pitch-entry. For 10 out of 20 variables measured after pitch-entry, values reduced from 0-5 min thereafter, and substitutes covered greater (p ˂0.05) total (+67 to +93 m) and high-speed (+14 to +33 m) distances during the first five min of match-play versus all subsequent epochs. Midfielders covered more distance (+41 m) per five min epoch than both attackers (p ˂0.001) and defenders (p = 0.016). Acknowledging the limitations of a solely movement data approach and the potential influence of other match-specific factors, such findings provide novel insights into the match-day demands faced by substitute soccer players. Future research opportunities exist to better understand the match-day practices of this population.

Profiling the Responses of Soccer Substitutes: A Review of Current Literature.

Depending upon competition regulations, the laws of soccer allow between three and an unlimited number of substitutions that can be made on either a permanent or rolling basis. Substitutes are typically introduced to minimise/offset the effects of fatigue, alter tactics, replace players deemed as underperforming or injured, and/or give playing time to youth players or to squad members returning from injury. While the match-day practices of substitutes include participation in the pre-match warm-up, and sporadic periods of rewarm-up activity, it is currently unclear as to whether these pre-entry preparations facilitate optimal match performance thereafter. Acknowledging the contextual factors that possibly influence substitutes' performance, this review summarises the presently available literature on soccer substitutes, and makes recommendations for future research. Literature searching and screening yielded 13 studies, which have typically focused on characterising: (1) the patterns, including timing, of substitutes' introduction; (2) indices of match-performance; and (3) the emotional experiences of soccer substitutes. The majority of substitutions occur after the first-half has ended (i.e. at half-time or during the second-half), with introduced players exceeding the second-half physical performances of those who started the match. Observations of progressive improvements in running performance as playing time increases, and findings that substitutes mostly experience negative emotions, highlight the potential inadequacies of pre-match preparations, and present future research opportunities. Additional work is therefore needed to confirm these findings and to determine the efficacy of current preparation strategies, thereby providing opportunities to assess then address substitutes' pre-pitch entry preparations, on-field performance and emotional responses.

The Perceived Psychological Responsibilities of a Strength and Conditioning Coach.

Radcliffe, JN, Comfort, P, and Fawcett, T. The perceived psychological responsibilities of a strength and conditioning coach. J Strength Cond Res 32(10): 2853-2862, 2016-Research is limited in exploring the specific psychology-oriented responsibilities of the strength and conditioning professional. The present research explored the psychological responsibilities adopted by accredited strength and conditioning coaches. Participants comprised 10 coaches working within the United Kingdom, 3 within the United States, and 5 within Australia offering a cross-section of experience from various sport disciplines and educational backgrounds. Participants were interviewed either in person or via Skype. Thematic clustering was followed using interpretative phonological analysis to identify common themes. Over half (61%) of the respondents reported that their position as a strength and conditioning coach required additional psychology-oriented responsibilities. These comprised a counseling role in the absence of a psychologist and the use of "softer skills" in a mentoring role to the athlete during a challenging situation. The coach could play an influential role in shaping the mentality of the team. The coach identifies how the role results in working to relay information from the athlete to other support staff and similarly from the support staff to the athlete. In addition to identifying the resonant psychology-oriented responsibilities, discussion is made with specific focus on the ethical boundary within which strength and conditioning coaches must reside regarding the competencies to provide psychological support.

Barriers to the Prescription of Psychological Strategies by Strength and Conditioning Specialists.

Radcliffe, JN, Comfort, P, and Fawcett, T. Barriers to the prescription of psychological strategies by strength and conditioning specialists. J Strength Cond Res 32(7): 1948-1959, 2018-The purpose of this article was to explore the barriers to strength and conditioning coaches integrating psychological strategies within the strength and conditioning practice. The sample of accredited strength and conditioning coaches comprised 10 subjects working within the United Kingdom, 3 within the United Sates, and 5 within Australia offering a cross section of experience from a range sporting disciplines and educational backgrounds. Subjects were interviewed using semistructured interviews and thematic clustering was used using interpretative phenomenological analysis to identify common themes. It was evident that not incorporating psychological strategies into strength and conditioning practice could be attributed to either internal, personally governed beliefs, or external, environmentally governed situations. Internal sources consisted of insufficient knowledge either regarding the value of psychological strategies or methods of implementing such techniques; in addition, the implementation of psychological techniques was outside the remit of the coach and difficulty existed in demonstrating the effectiveness of interventions. External causes consisted of a lack of time, insufficient control and authority of training session content, and athletes' negative perceptions. Recommendations are made on the basis of eliminating the observed barriers to the inclusion of psychological strategies. This included the use of education programs for both strength and conditioning coaches and organizational gatekeepers and the suggestion for increased collaboration with qualified psychologists.

Psychological Strategies Included by Strength and Conditioning Coaches in Applied Strength and Conditioning.

This study provided the basis by which professional development needs can be addressed and add to the applied sport psychology literature from an underresearched sport domain. This study endeavored to use qualitative methods to explore the specific techniques applied by the strength and conditioning professional. Eighteen participants were recruited for interview, through convenience sampling, drawn from a previously obtained sample. Included in the study were 10 participants working within the United Kingdom, 3 within the United States, and 5 within Australia offering a cross section of experience from ranging sport disciplines and educational backgrounds. Participants were interviewed using semistructured interviews. Thematic clustering was used by interpretative phonological analysis to identify common themes. The practitioners referred to a wealth of psychological skills and strategies that are used within strength and conditioning. Through thematic clustering, it was evident that a significant emphasis is on the development or maintenance of athlete self-confidence specifically with a large focus on goal setting. Similarly, albeit to a lesser extent, there was a notable attention on skill acquisition and arousal management strategies. The strategies used by the practitioners consisted of a combination of cognitive strategies and behavioral strategies. It is important to highlight the main psychological strategies that are suggested by strength and conditioning coaches themselves to guide professional development toward specific areas. Such development should strive to develop coaches' awareness of strategies to develop confidence, regulate arousal, and facilitate skill and technique development.

The perception of psychology and the frequency of psychological strategies used by strength and conditioning practitioners.

The study aimed to first examine the frequency of the psychological skills and strategies of strength and conditioning practitioners and second distinguish between demographic differences in relation to psychological skills and strategy use. The Strength and Conditioning Sport Psychology Questionnaire was developed to measure the frequency of use of 11 subscales. These consisted of goal setting, imagery, self-talk, mental toughness, attention control, relaxation, stress management, adherence, activation, self-confidence, and ego management. Each subscale demonstrated acceptable internal validity ale (mean interitem correlations ranged as 0.227-0.427). The instrument allowed up to 5 open-ended responses concerning skills considered most important to strength and conditioning practice and up to 5 psychological attributes considered detrimental within strength and conditioning. One hundred and two participants met the inclusion criteria (90 men and 12 women; age 34.7 ± 9.7 years; experience 7.4 ± 5.2 years; part time 36.5%; full time 63.5%). The respondents were registered with the following organizations: United Kingdom Strength and Conditioning Association: 41, National Strength and Conditioning Association: 48 and Australian Strength and Conditioning Association (ASCA): 48. Goal setting was found to be the most frequently used skill with mental imagery the least used with significant differences identified in the frequency of skill use. The strategies deemed to be most important were motivation and confidence with the most debilitating factors identified as a lack of motivation and a lack of confidence. When comparing demographics, overall skill use varied between practitioners with different experience with more experienced practitioners having greater skill use, both overall and particular individual skills. Participants accredited by the ASCA had a greater psychological skill use than those accredited by other bodies.