Bruno Mendes

The acute:chonic workload ratio in relation to injury risk in professional soccer

OBJECTIVES To examine the association between combined sRPE measures and injury risk in elite professional soccer. DESIGN Observational cohort study. METHODS Forty-eight professional soccer players (mean±SD age of 25.3±3.1 yr) from two elite European teams were involved within a one season study. Players completed a test of intermittent-aerobic capacity (Yo-YoIR1) to assess players injury risk in relation to intermittent aerobic capacity. Weekly workload measures and time loss injuries were recorded during the entire period. Rolling weekly sums and week-to-week changes in workload were measured, allowing for the calculation of the acute:chronic workload ratio, which was calculated by dividing the acute (1-weekly) and chronic (4-weekly) workloads. All derived workload measures were modelled against injury data using logistic regression. Odds ratios (OR) were reported against a reference group. RESULTS Players who exerted pre-season 1-weekly loads of ≥1500 to ≤2120AU were at significantly higher risk of injury compared to the reference group of ≤1500AU (OR=1.95, p=0.006). Players with increased intermittent-aerobic capacity were better able to tolerate increased 1-weekly absolute changes in training load than players with lower fitness levels (OR=4.52, p=0.011). Players who exerted in-season acute:chronic workload ratios of >1.00 to <1.25 (OR=0.68, p=0.006) were at significantly lower risk of injury compared to the reference group (≤0.85). CONCLUSIONS These findings demonstrate that an acute:chronic workload of between 1.00 and 1.25 is protective for professional soccer players. A higher intermittent-aerobic capacity appears to offer greater injury protection when players are exposed to rapid changes in workload in elite soccer players. Moderate workloads, coupled with moderate-low to moderate-high acute:chronic workload ratios, appear to be protective for professional soccer players.

High-speed running and sprinting as an injury risk factor in soccer: Can well-developed physical qualities reduce the risk?

OBJECTIVES This study investigated the association between high-speed running (HSR) and sprint running (SR) and injuries within elite soccer players. The impact of intermittent aerobic fitness as measured by the end speed of the 30-15 intermittent fitness test (30-15VIFT) and high chronic workloads (average 21-day) as potential mediators of injury risk were also investigated. DESIGN Observational Cohort Study. METHODS 37 elite soccer players from one elite squad were involved in a one-season study. Training and game workloads (session-RPE×duration) were recorded in conjunction with external training loads (using global positioning system technology) to measure the HSR (>14.4kmh-1) and SR (>19.8kmh-1) distance covered across weekly periods during the season. Lower limb injuries were also recorded. Training load and GPS data were modelled against injury data using logistic regression. Odds ratios (OR) were calculated with 90% confidence intervals based on 21-day chronic training load status (sRPE), aerobic fitness, HSR and SR distance with these reported against a reference group. RESULTS Players who completed moderate HSR (701-750-m: OR: 0.12, 90%CI: 0.08-0.94) and SR distances (201-350-m: OR: 0.54, 90%CI: 0.41-0.85) were at reduced injury risk compared to low HSR (≤674-m) and SR (≤165-m) reference groups. Injury risk was higher for players who experienced large weekly changes in HSR (351-455-m; OR: 3.02; 90%CI: 2.03-5.18) and SR distances (between 75-105-m; OR: 6.12, 90%CI: 4.66-8.29). Players who exerted higher chronic training loads (≥2584 AU) were at significantly reduced risk of injury when they covered 1-weekly HSR distances of 701-750m compared to the reference group of <674m (OR=0.65, 90% CI 0.27-0.89). When intermittent aerobic fitness was considered based on 30-15VIFT performance, players with poor aerobic fitness had a greater risk of injury than players with better-developed aerobic fitness. CONCLUSIONS Exposing players to large and rapid increases in HSR and SR distances increased the odds of injury. However, higher chronic training loads (≥2584 AU) and better intermittent aerobic fitness off-set lower limb injury risk associated with these running distances in elite soccer players.

Internal training load and its longitudinal relationship with seasonal player wellness in elite professional soccer

Monitoring internal training load has been extensively used and described within team sport environments, however when compared to internal physiological measures such as heart rate (HR) and rating of perceived exertion (RPE), the literature is sparse. The primary aim of this investigation study was to assess differences of playing position on ITL, session-RPE and wellness across two different training microcycles (1 vs. 2 competitive games), in addition with examining the relationship between ITL and Hoopers Index across an entire season. Thirty-five professional soccer players from the Portuguese premier league participated in the study (25.7±5.0years; 182.3±6.4cm; 79.1±7.0kg). Analysis of variance revealed higher values of DOMS (Means(M): 3.33 vs. 3.10; p=0.001; effect Size (ES)=0.087), fatigue (M: 3.18 vs. 2.99; p=0.001; ES=0.060) and HI (M: 11.85 vs. 11.56; p=0.045; ES=0.034) in 2-game weeks compared with 1-game weeks. Correlation between ITL and HI levels found significant negative correlations between ITL and DOMS (ρ=-0.156), ITL and sleep (ρ=-0.109), ITL and fatigue (ρ=-0.225), ITL and stress (ρ=-0.188), and ITL and HI (ρ=-0.238) in 2-game weeks. Results from 1-game microcycle only highlighted negative correlations between ITL and stress (ρ=-0.080). It was concluded from the study that greater fatigue potential, muscle soreness, stress and ITL was significantly more apparent within a 2-game microcycle. As a result, care should be taken when planning the lead into and out of a 2-game fixture microcycle highlighting key specific recovery strategies to damped the increased stress effect. Additionally, the potential utilization of squad rotation strategies may be a positive approach with aim of managing the fatigue effect.

Effects of roller massager on muscle recovery after exercise-induced muscle damage.

ABSTRACT Two experiments (n = 10) were conducted to determine the effects of roller massager (RM) on ankle plantar flexor muscle recovery after exercise-induced muscle damage (EIMD). Experiment 1 examined both functional [i.e., ankle plantar flexion maximal isometric contraction and submaximal (30%) sustained force; ankle dorsiflexion maximal range of motion and resistance to stretch; and medial gastrocnemius pain pressure threshold] and morphological [cross-sectional area, thickness, fascicle length, and fascicle angle] variables, before and immediately, 1, 24, 48, and 72 h after an EIMD stimulus. Experiment 2 examined medial gastrocnemius deoxyhaemoglobin concentration kinetics before and 48 h after EIMD. Participants performed both experiments twice: with (RM) and without (no-roller massager; NRM) the application of a RM (6 × 45 s; 20-s rest between sets). RM intervention did not alter the functional impairment after EIMD, as well as the medial gastrocnemius morphology and oxygenation kinetics (P > 0.05). Although, an acute increase of ipsilateral (RM = + 19%, NRM = −5%, P = 0.032) and a strong tendency for contralateral (P = 0.095) medial gastrocnemius pain pressure threshold were observed. The present results suggest that a RM has no effect on plantar flexors performance, morphology, and oxygenation recovery after EIMD, except for muscle pain pressure threshold (i.e., a soreness).

Analysis of a training mesocycle and positional quantification in elite European soccer players

Ensuring adequate levels of training and recovery at the elite level of professional soccer to maximise player performance has continued to drive the necessity to monitor the training load and physical training output of soccer players. The aim of this investigation was to analyse a training mesocycle whilst quantifying positional demands imposed on elite European soccer players. Sixteen players were assessed using global positioning systems and ratings of perceived exertion over a competitive training six-week mesocycle period. The positional demands and training loads were analysed in addition to match conditions (match location, match score) and player’s age. Results from the investigation revealed that typical daily training loads (i.e. total distance, high-intensity distance, sprint distance, average speed, ratings of perceived exertion) did not differ throughout each week of the mesocycle in-season period. Further analysis revealed training loads were significantly lower on match day-1 when compared to training loads on match day-2, match day-3 and match day-4 preceding a match (p < 0.05). Significant differences in physical outputs were also found between match day-2, match day-3 and match day-4 highlighting a structured periodised tapered approach (p < 0.05). Lower average speeds were reported in training post-successful matches compared to defeats (p < 0.05), and more specifically when a match was played away compared to home fixtures (p < 0.05). To conclude, practitioners can maintain a uniformed and structured training load mesocycle whilst inducing variation of the physical outputs during the microcycle phase. Additionally, the investigation also provides a tapering approach that may induce significant variation of the positional demands.

Analysis of positional training loads (ratings of perceived exertion) during various-sided games in European professional soccer players

The primary aim of the study was to perform a comparative analysis of the positional training loads during various game formats among European professional soccer players. Twenty-two male professional soccer players participated in the investigation and were divided into their tactical positional roles for analysis. Ratings of perceived exertion were collected daily and corresponded to specific formatted game types (small-sided games; large-sided games; large-sided games within a smaller area size) implemented as part of the weekly periodised training structure. Across the sample period, only one game per week training scenarios were analysed (9 × small-sided games; 9 × large-sided games; 9 × large-sided games within a smaller area size). Analysis of the mean ratings of perceived exertion between various game formats revealed significant differences between large-sided games within a smaller area size vs. small-sided games (5.53 vs. 7.79; p = 0.007); however, no differences were presented between small-sided games vs. large-sided games format types (7.9 vs. 7.35; p > 0.05). No differences between mean ratings of perceived exertion and small-sided games and large-sided games, respectively, were found. Differences were shown between positional demands during large-sided games within a smaller area size game type formats, with wide forwards reporting higher mean ratings of perceived exertion values when compared against centre forwards (p = 0.02). Therefore, within a periodised microcycle, variance of game formats can be used to manipulate training loads, manage accumulation of fatigue through a tapering method in order to facilitate optimal match preparation. Furthermore, players of certain position types may require additional training stimulus to induce the desired physical adaptations.

Post-match sleeping behavior based on match scheduling over a season in elite football players

ABSTRACT Objectives: (1) To objectively monitor and describe sleeping patterns of elite football players after matches during a competitive season and (2) to describe the variability in sleeping patterns between these contexts. Methods: Actimetry was used to determine sleeping patterns of 25 elite players from 1 Portuguese First League (Liga NOS) club for at least 3 normal training days (TDs) as a baseline and then after various matches, including home (HM), away (AM), day (DM) and night (NM). Actimetry-derived sleep measures included total sleep duration (TSD), sleep onset latency, sleep efficiency (SE) and wake episode duration. Results: On TD, both TSD (6:36 h) and SE (85%) were below recommended healthy ranges of 7–8 h and >90%, respectively. TSD was even less after NM compared to both TD (–65 min) and DM (–65 min) (P < 0.05), without differences between DM and TD (P > 0.05). Additionally, TSD was greater in AM compared to HM (+77 min, P = 0.001). Conclusions: The primary findings of this study were the significant reduction in total sleep duration and later bedtime following (night) matches compared to normal training days.

Daily and weekly training load and wellness status in preparatory, regular and congested weeks: a season-long study in elite volleyball players

ABSTRACT The study aimed to assess the changes in the perceived internal load and wellness status of volleyball players in preparatory, regular (i.e. uncongested), and congested weeks during a full season. Thirteen elite volleyball players were studied (237 training sessions and 37 official matches). Session-RPE, muscle soreness, stress, fatigue, sleep quality, and the Hooper Index were measured daily using questionnaires. Training sessions were classified based on the number of matches per week and the days before or after a match: preparatory (no match), regular (one match), and congested weeks (two or more matches). Pairwise comparisons found significantly greater session-RPE scores (p < 0.05) one day before the match (304.74 A.U.), in regular weeks than in congested weeks (204.40 A.U.). Matches during the congested weeks (364.71 A.U.) had significantly higher session-RPE scores (p < 0.05) than regular weeks (252.97 A.U.). Three days before the match involved significantly higher values of muscle soreness, fatigue, stress, and sleep quality than regular weeks. Match accumulation increased the session-RPE training load of the matches. This study provides insights into the training load and well-being status before competition, for training the day of competition, and after the competition.

Wellbeing perception and the impact on external training output among elite soccer players.

OBJECTIVES The objective of the investigation was to observe the impact of player wellbeing on the training output of elite soccer players. DESIGN Prospective cohort design. METHODS Forty-eight soccer players (age: 25.3±3.1years; height: 183±7cm; mass: 72±7kg) were involved in this single season observational study across two teams. Each morning, pre-training, players completed customised perceived wellbeing questionnaires. Global positioning technology devices were used to measure external load (total distance, total high-speed running distance, high speed running, player load, player load slow, maximal velocity, maximal velocity exposures). Players reported ratings of perceived exertion using the modified Borg CR-10 scale. Integrated training load ratios were also analysed for total distance:RPE, total high speed distance:RPE player load:RPE and player load slow:RPE respectively. RESULTS Mixed-effect linear models revealed significant effects of wellbeing Z-score on external and integrated training load measures. A wellbeing Z-score of -1 corresponded to a -18±2m (-3.5±1.1%), 4±1m (-4.9±2.1%,) 0.9±0.1kmh-1 (-3.1±2.1%), 1±1 (-4.6±2.9%), 25±3AU (-4.9±3.1%) and 11±0.5AU (-8.9±2.9%) reduction in total high speed distance, high speed distance, maximal velocity, maximal velocity exposures, player load and player load slow respectively. A reduction in wellbeing impacted external:internal training load ratios and resulted in -0.49±0.12mmin-1, -1.20±0.08mmin-1,-0.02±0.01AUmin-1 in total distance:RPE, total high speed distance:RPE and player load slow:RPE respectively. CONCLUSIONS The results suggest that systematic monitoring of player wellbeing within soccer cohorts can provide coaches with information about the training output that can be expected from individual players during a training session.

A contemporary multi-modal mechanical approach to training monitoring in elite professional soccer

ABSTRACT Objectives: Understanding movements and mechanical demands of elite soccer players during training and competitive stressors is important for the support provision of player performance. Continued appreciation to quantify and monitor training load (TL) is apparent, however reporting multi-modal approaches in-line with competitive match-play demands remain limited. The investigation aimed to highlight a multimodal training monitoring method and its relationship to match-play. Subjects: 29 elite European soccer players participated were assessed (26.7 ± 4.07 years, height 183.4 ± 5.87 cm, body mass 78.4 ± 8.03 kg, 57.55 ± 5.32 ml.kg-1.min-1 and body composition 54.12 ± 13.65 mm) with daily TL and competitive match-load data in order to quantify the relationship between both. Methods: Key match-day (MD) data and TL was analysed across a 20-week in-season period. Results: Results reported significant TL differences between training days (TDs) and TDs and competitive MD data, in addition to significant differences between TDs for both volume- and intensity- session scores (p < 0.05). No differences were found between MD-1 and MD-2 session scores. Conclusion: To specific specific multi-modal approach used allows practitioners to combine key mechanical volume and intensity metrics as part of an athlete or player monitoring strategy and ensure a greater focus on targeted physical stressors.