Training load monitoring in team sports: A novel framework separating physiological and biomechanical load-adaptation pathways

There have been considerable advances in monitoring the training load in running-based team sports in recent years. Novel technologies nowadays offer ample opportunities to continuously monitor the activities of a player. These activities lead to internal biochemical stresses on the various physiological sub-systems. However, they also cause internal mechanical stresses on the various musculoskeletal tissues. Based on the amount and periodization of these stresses, the sub-systems and tissues adapt. So by monitoring external loads one hopes to estimate internal loads to predict adaptation, and this through understanding the load-adaptation pathways. We propose a new theoretical framework in which physiological and biomechanical load-adaptation pathways are considered separately, shedding a new light on some of the previously published evidence. We hope that it can help the various practitioners in this field (trainers, coaches, medical staff, sport scientists) to align their thoughts when considering the value of monitoring load, and that it can help researchers design experiments that can better rationalise training load monitoring for improving performance whilst preventing injury

The effect of concurrent training organisation in youth elite soccer players

Purpose: This study compared the adaptive responses to two concurrent training programmes frequently used in professional soccer. Methods: Fifteen youth soccer players (17.3 ± 1.6 years, 1.82 ± 0.06 m, 77.0 ± 7.3 kg; VO peak, 62.0 ± 4.7 ml kg min) who compete in the English Premier League volunteered for this study. In addition to completing their habitual training practices, the participants were asked to alter the organisation concurrent training by performing strength (S) training either prior to (S + E, n = 8) or after (E + S, n = 7) soccer-specific endurance training (E) 2d wk for 5 wk. Results: With the exception of 30 m sprint, IMVC PF, quadriceps strength (60°/s, 180°/s, 120°/s) pooled data revealed training effects across all other performances measures (P < 0.05). Whilst ANCOVA indicated no significant interaction effects for training condition, the difference between the means divided by the pooled standard deviation demonstrated large effect sizes in the E + S condition for in HBS 1-RM [S + E vs E + S; −0.54 (9.6 %) vs −1.79 (19.6 %)], AoP-M [−0.72 (7.9 %) vs −1.76 (14.4 %)], SJ [−0.56, (4.4 %), vs −1.08, (8.1 %)], IMVC-LR; [−0.50, (20.3 %) vs −1.05 (27.3 %)], isokinetic hamstring strength 60°/s [−0.64, (12.2 %) vs −0.95 (19.2 %)], 120°/s [−0.78 (27.9 %) vs −1.55 (23.3 %)] and isokinetic quadriceps strength 180°/s  [−0.23 (2.5 %) vs −1.52 (13.2 %)]. Conclusion: Results suggest the organisation of concurrent training, recovery time allocated between training bouts and the availability nutrition may be able to modulate small but clinically significant changes in physical performance parameters associated with match-play. This may have practical implications for practitioners who prescribe same day concurrent training protocols

Implementing concurrent-training and nutritional strategies in professional football: a complex challenge for coaches and practitioners

Purpose: To study concurrent-training (CT) and nutritional practices within a professional soccer team. Methods: Twenty-one professional football players competing in the English professional league participated in this study (mean ± standard deviations [M ± SD] 26 ± 4 years, stature 1.84 ± 0.1 m, body mass 83 ± 7 kg, VO2max; 58 ± 3 ml · kg−1 · min−1). A range of internal and external training metrics, the organisation of CT (training sequence, training rest period between bouts) and the nutritional intake around CT (timing, type and quantity) was collected for 10 weeks. Results: CT; n = 17 (endurance-training [ET] + resistance-training [RT]; n = 11; RT + ET; n = 6) rest period between bouts was not consistent and varied depending on the sequence of CT (RT + ET, 75 ± 48 min; ET + RT; 60 ± 5 min; P = 0.04). sRPE of football-specific ET was higher in RT + ET (RT + ET, 7 ± 1; ET + RT, 6 ± 1; P = 0.05). The timing of meals around training was influenced by the organisation of CT. Subsequently, CHO consumption before training session one was significantly less in RT + ET (CHO 0.10 ± 0.5 g · kg−1 vs. CHO 0.45 ± 0.2 g · kg−1). Conclusion: The present data demonstrate that the organisation of CT (i.e., exercise order and/or recovery time between bouts) and nutrition (i.e., timing of meal intake) can be unsystematic in the applied environment. The organisation of training and nutrition might influence the players’ ability to perform high-intensity actions in secondary training sessions and could potentially impact acute metabolic processes associated with muscle recovery and muscle adaptation

Seasonal Training-Load Quantification in Elite English Premier League Soccer Players

Purpose: To quantify the seasonal training load completed by professional soccer players of the English Premier League. Methods: Thirty players were sampled (using GPS, heart rate, and rating of perceived exertion [RPE]) during the daily training sessions of the 2011–12 preseason and in-season period. Preseason data were analyzed across 6 × 1-wk microcycles. In-season data were analyzed across 6 × 6-wk mesocycle blocks and 3 × 1-wk microcycles at start, midpoint, and end-time points. Data were also analyzed with respect to number of days before a match. Results: Typical daily training load (ie, total distance, high-speed distance, percent maximal heart rate [%HRmax], RPE load) did not differ during each week of the preseason phase. However, daily total distance covered was 1304 (95% CI 434–2174) m greater in the 1st mesocycle than in the 6th. %HRmax values were also greater (3.3%, 1.3–5.4%) in the 3rd mesocycle than in the first. Furthermore, training load was lower on the day before match (MD-1) than 2 (MD-2) to 5 (MD-5) d before a match, although no difference was apparent between these latter time points. Conclusions: The authors provide the 1st report of seasonal training load in elite soccer players and observed that periodization of training load was typically confined to MD-1 (regardless of mesocycle), whereas no differences were apparent during MD-2 to MD-5. Future studies should evaluate whether this loading and periodization are facilitative of optimal training adaptations and match-day performance

Hormonal responses during two different concurrent-training trials in youth elite soccer players: does changing the organisation of training impact the hormonal response to concurrent exercise?

BACKGROUND: There are no data describing the acute hormonal responses to concurrent-training programmes in youth elite soccer players. Therefore, the aim of this study was to describe the total testosterone (T), cortisol (C), and growth hormone (hGH) responses during two same-day concurrent-training (CT) trials in elite soccer players. METHODS: n=13 youth elite players (age: 17.0±0.2 yrs; height, 1.80±0.07 m; body mass, 73.1±5.7 kg; O2 max, 64.4±4.8ml-1.kg-1.min-1) from an English premier league soccer club completed two CT trials. ‘Trial 1’ (CT1); E (10.30h) followed by S (14.00h) and Trial 2 (CT2); strength-training (S) 09.00h followed by a soccer-specific endurance-training session (E) at 10.30h. Venous blood samples were collected at 5 time-points around training and food intake (T1; 08.00h, T2; 09.45h, T3; 12.30h, T4; 13.45h and T5; 15.15h) and analysed for T (nmol/L) and C (nmol/L) and hGH (ug/L). RESULTS: There was no main effects found between exercise conditions for any hormones (T; P=0.22, C; P=0.07, hGH; P=0.21). Effect size analysis revealed a moderate effect for T at T3 (ES=0.63, CT1; 18.4±3.8, CT2; 15.7±4.7 nmol/L-1). A moderate effect for T area under the curve (AUC) was observed between conditions (CT1; 300±76 versus CT2; 244 ± 81 [AU]; ES=0.71). A moderate effect was apparent for C concentrations T4 in (ES=-0.95, CT1; 230±69, CT2; 314±105 nmol/L-1). Moderate effect sizes were observed at T3 and T4 (ES=0.82, CT1; 1.28±1.17, CT2; 0.47±0.75, ES=0.72, CT1; 0.11±0.05, CT2; 0.07±0.06 ug/L-1 respectively). A moderate effect for hGH AUC was observed between trials (CT1; 14±11 versus CT2; 5±9; [AU], ES=-1.08). CONCLUSIONS: The organisation of the concurrent-training protocols used in this study has a negligible impact upon the acute T, C and hGH in youth elite soccer players

Asymmetry after Hamstring Injury in English Premier League: Issue Resolved, Or Perhaps Not?

Hamstring injuries constitute one of the most concerning injuries in English Premier League football, due to its high primary incidence but also its recurrence. Functional methods assessing hamstring function during high-risk performance tasks such as sprinting are vital to identify potential risk factors. The purpose of this study was to assess horizontal force deficits during maximum sprint running on a non-motorized treadmill in football players with previous history of hamstring strains as a pre-season risk-assessment in a club setting. 17 male football players from one Premier League Club were divided into 2 groups, experimental (n= 6, age = 24.5 ± 2.3 years) and control (n= 11, age = 21.3 ± 1.2 years), according to history of previous hamstring injury. Participants performed a protocol including a 10 seconds maximum sprint on a non-motorized treadmill. Force deficits during acceleration phase and steady state phases of the sprint were assessed between limbs and between groups. The main outcome measures were horizontal and vertical peak forces during the acceleration phase or steady state. There were no significant differences in peak forces between previously injured and non-injured limbs, or between groups, challenging the ideas around functional force deficits in sprint running as a diagnostic measure of hamstring re-injury risk

An Intensive Winter Fixture Schedule Induces a Transient Fall in Salivary IgA in English Premier League Soccer Players

We examined the effects of an intensive fixture schedule on salivary IgA (SIgA) concentration in professional soccer players from the English Premier League. Salivary samples were obtained from 21 males who participated in 7 games over a 30-day period during December 2013 and January 2014 (games 1-5 occurred in a 15-day period). Salivary-IgA decreased (P 0.05) from game 1 (91 ± 18 and 99 ± 21 μg.mL-1, respectively). Data demonstrate for the first time that a congested winter fixture schedule induces detectable perturbations to mucosal immunity in professional soccer players