Training Load and Player Monitoring in High-Level Football: Current Practice and PerceptionsBy R Akenhead & G Nassis in Int J Sports Physiol Perform, Jul 2016

What did they do? Surveyed practitioners from 82 professional football clubs, with questions relating to how they quantify training load, monitor player’s responses, and rate the effectiveness of monitoring.

Why is it important? Providing a snapshot of the current practices and perceptions of monitoring within elite football will serve to highlight the challenges faced by practitioners and stimulate further industry-relevant applied research.

Things to consider: A convenience sample approach was used and not all high-level football clubs were approached. In total, 48 surveys were returned (59%), the majority came from clubs based in England (23), the USA (7) and France (4). Thus, a responder bias may be present.Take home message: No universally adopted monitoring approach exists, although HR, GPS, and self-report questionnaires are commonly used measures. Despite the importance of monitoring, its perceived impact on injury prevention and performance enhancement is lower than expected.

Influence of football match time-motion parameters on recovery time course of muscle damage and jump abilityBy M de Hoyo et al. in J Sports Sci, Mar 2016

What did they do? Analysed the post-match recovery course of creatine kinase and countermovement jump parameters in relation to individual match activity parameters.

Why is it important? It is believed that the magnitude of physiological alterations elicited by match play is associated with specific movement demands (i.e. number of sprints, accelerations etc.). Additional knowledge on the physiological effects of a football match may allow the design of individualised recovery strategies.

Things to consider: The correlations in the current study were determined after only one match, and should therefore be interpreted with caution. Repeated monitoring of responses after matches with varying demands could provide clearer results.

Take home message: Greater distances covered at higher speeds, as well as accelerations and decelerations are associated with greater muscle damage and impaired countermovement jump performance. However, players seem to have varying responses in said parameters to the match demand. Whether these correlate with different activity profiles, was not examined here.

Let us stop throwing out the baby with the bathwater: towards better analysis of longitudinal injury dataBy C Finch & S Marshall in Br J Sports Med, Jun 2016 [Editorial]

What did they do? Described the numerous limitations often apparent with longitudinal injury data analysis.

Why is it important? Conclusions made from epidemiological or prospective cohort studies that do not account for exposure time and/or recurrent/multiple injuries to the same player provide only partial insights.

Things to consider: Collecting exposure data (amount of time where a football-related injury could occur) can be a difficult task for large-scale studies. Likewise, comprehensive injury recording that accounts for re-injuries to the same player is challenging with large sample sizes. Estimating exposure is possible, however should be noted as a limitation.

Take home message: Ideally, exposure time and multiple injuries should be taken into account when analysing longitudinal injury data. While epidemiological and prospective cohort studies that do not take exposure time and multiple injuries to the same player into account are limited, they are not necessarily useless; associations between tests and outcomes can still be highlighted.

Practitioners’ perceptions of the soccer extra-time period: Implications for future researchBy L Harper et al. in PLoS ONE, Jul 2016

What did they do? Surveyed applied practitioners working in football and asked them whether they perceived the extra-time period as important and which direction future research in this area should take.

Why is it important? Relatively little research concerning the extra-time period in football has been published. It is important for research to reflect the ‘needs’ of applied sport scientists. Injury epidemiology and acute injury risk related to extra-time were both rated as worthy of future investigation.

Things to consider: Extra-time only occurs during knockout competitions hence it only makes up a small fraction of overall playing time for professional players during a season. In order to accumulate sufficient exposure time and number of injuries for statistical analysis numerous teams would likely need to be observed for multiple seasons.

Take home message: Many applied practitioners believe future research concerned with the extra-time period should focus on injury risk. Such work need not rely on actual match data, with extra-time simulation protocols a potential avenue for initial descriptive studies.

Football QuarterlyAugust 2016

Ross Julian, Robert McCunn, Denny Noor & Emiel Schulze

Female FootballMatch physical performance of elite female soccer players during international competitionBy N Datson et al. in J Strength Cond Res, Jul 2016

What did they do? Collected physical match activity for 107 players over two seasons of elite competition. Players were distinguished by playing position to determine the influences on physical match activity, differences in activity between halves, and within halves.

Why is it important? A gender-specific and comprehensive understanding of the physical demands of match play is necessary in order to apply a systematic approach to training and testing protocols.

Things to consider: Generalised classifications of activity are derived from male datasets. Although these are often used in research, they tend to underestimate match-play demands by reducing the amount of high-speed activities completed by female players. Specific thresholds for a female population are required.

Take home message: The present study highlights the vast differences in the physical match demands between playing positions. This information suggests practitioners should provide position specific conditioning for female footballers.

Injuries and Prevention Fatigue and Recovery Match AnalysisMatch-to-match variability in high-speed running activity in a professional soccer teamBy C Carling et al. in J Sports Sci, May 2016

What did they do? Analysed high-speed match activities (>19.8km/h) throughout a season for 12 elite players. This made it possible to determine the match-to-match variability in a variety of frequently reported measures of physical activity.

Why is it important? Measures of high-speed activity are frequently reported in scientific literature and considered important in practice. In order to make appropriate assumptions about such findings, the degree to which these measures usually vary is important to know.

Things to consider: Although playing position and team tactics were stable between measurements and being in or out of ball possession was separated, opponent quality and scoreline were not incorporated in the analyses, which could have led to increased variation.

Take home message: The overall variance of ~20% (CV) stresses the complexity of interpreting match activity. These values increased up to ~100% when taking ball possession into consideration. Variance differed between playing positions, which should be kept in mind. Interestingly, relating high-speed activity to individual fitness decreased variance.

Seasonal pacing - Match importance affects activity in professional soccer By D Link & M de Lorenzo in PLoS ONE, Jun 2016

What did they do? Analysed match activity over two seasons of the two highest German football leagues to determine whether players changed their activity according to the effect of a possible outcome (importance).

Why is it important? The psychological aspects of performance in elite football are often left out when analysing physical activity. Pacing could be an apparent factor, with players refraining from going all out every minute of every match.

Things to consider: Although playing intensity dropped with the calculated match importance, it should be noted that the study only found matches of low importance late in the seasons, when teams could not move in the table anymore. It seems unlikely that all matches earlier in the season are important, since a match for a team battling for relegation against a team playing for the title seems of less importance than a match against a close competitor.

Take home message: Significant differences in physical activity were found for changing match importance. Thereby it appears that pacing does play in role within the final stages of the season. The importance during earlier phases has to be determined.

Is muscular strength balance influenced by menstrual cycle in female soccer players?By M Dos Santos Andrade et al. in J Sports Med Phys Fitness, Apr 2016 What did they do? Completed two identical experimental sessions with 26 female soccer players during the two main phases of the menstrual cycle (follicular & luteal phase). Twelve male soccer players formed a control group.

Why is it important? Muscle imbalance has been found to correlate with lower extremity injuries in a general female athletic population. Understanding the effects of menstrual cycle phase and muscular strength balances in female footballers, where said injuries occur regularly, could be important for the management of injury risk.

Things to consider: Although cycles of physiological length were determined through menstruation calendars, without hormone values, it is not known whether cycle abnormalities were apparent and/or included into the main analysis.

Take home message: Isokinetic hamstring-to-quadriceps torque strength balance ratio was diminished in the follicular phase compared to the luteal phase of the non-dominant knee. This information may be useful for practitioners when planning training drills or for the consideration of potential injury risk in training or matches.

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