Liverpool’s Academic Research (Abstracts only)

Revealed: The science behind Liverpool FC – This Is Anfield

The backroom sports science team, led by Ryland Morgans, has recently published a number of peer-reviewed articles that ultimately improves the Reds’ knowledge of the game, supporting the manager and the players. Research was conducted by all full-time fitness staff at the Club and consultants Professor Barry Drust and Dr James Morton.

The sport science team work very closely with Brendan Rodgers, the coaches and physiotherapists. The fitness and science staff monitor the physical condition of players, the physical aspects of training and preparation as well as providing Rodgers with information about where players are when recovering in relation to upcoming matches.

Successful short passing frequency of defenders differentiates between top and bottom four English Premier League teams

Dominating ball possession during football matches may be a feature of successful English Premier League (EPL) teams. Yet, supporting evidence remains unclear. This study aimed to identify which performance indicators falling under the umbrella of possession separate teams that finish at the top versus teams that finish at the bottom of the EPL. Aggregated technical data for defending, midfield and attacking units obtained from all EPL matches played in one season were analysed. Decision tree induction was applied to a training dataset (N = 149). The final model involved five splits (Rsquare = 0.662). The variable with the largest contribution to the final decision tree model was total successful short passes made by defenders (G2 = 115). The second largest contribution was successful passes made in the opposition half by midfielders (G2 = 13), the third variable that contributed was unsuccessful passes opposition half made by defenders (G2 = 8). All other selected variables made negligible contributions (G2 < 2). This study provides novel findings suggesting that successful EPL teams utilise defenders to build-up play. Maintaining possession via short passes permits the attacking team to move the opponents around the pitch and wait for attacking opportunities to emerge.

Changes in physical performance variables in an English Championship League team across the competitive season: the effect of possession

This study examined changes in physical match performance of six players from an English Championship League team across the competitive season and examined the effect of team possession. Sprint and high intensity distances and frequency of efforts were all greatest in early-season, and were significantly reduced in both mid-and-late-season phases (all p < 0.0001). None of these variables were, however, related to team possession (p range = 0.2759 to 0.7411). Total distance covered on the other hand was sustained and did not significantly change over the season phases (p = 0.9219), but it was negatively associated with possession (p = 0.0080). This association suggests that physical demands were lower when this team was in possession of the ball. In summary, evidence of residual fatigue at mid-and-late-season was obtained from sprint and high intensity variables. Given possession was associated with a reduced total distance covered during matches, it may be speculated that better quality teams are able to maintain possession for longer periods of matches and thus require less recovery time due to reduced physical match demands.

Technical and physical performance over an English Championship League season

The English Championship League (ECL) has a demanding ten-month schedule exposing players to residual fatigue if they play the majority of matches, which could reduce physical and technical match performance towards the end of the season. Over one season we studied 11 ECL players who played the majority of matches to see if differences in physical and technical performance occurred.
From the home matches analysed, only total distance covered was different, it was highest at mid-season (December) compared to two months later (February). Team possession remained stable throughout the season and the relative total distance covered by the team was calculated to be less (72metres per minute) when the team were in possession. In summary, maintaining possession during matches may reduce physical demands imposed on players and help preserve performance throughout the season.

A Comparison of Physical and Technical Match Performance of a Team Competing in the English Championship League and Then the English Premier League Following Promotion

The changes in match demands when a team is promoted from the English Championship League (ECL) to the English Premier League (EPL) remain unknown. To date, estimates of between league differences are made using different teams. This study explores differences in physical and technical performance of players who competed in the ECL and then the EPL following promotion.
Although total distance covered over the season was the only measure to significantly differ between the ECL and EPL, the 3% increase in total distance in the EPL was deemed practically non-significant. In the EPL, players had an extra 57 ± 6 hours between matches, yet this had little effect on total, sprint and high intensity distances. In summary, higher league standard may not require greater physical capacity and developing a tactical strategy to suit the ability of players that is sustainable across leagues is important.

High-intensity training and salivary immunoglobulin A responses in professional top-level soccer players: effect of training

This study aimed 1)- to test the hypothesis that salivary immunoglobulin A (s-IgA) would vary with training intensity sessions (low intensity [LI] vs. high intensity sessions [HI]) during a traditional training program divided in 4 training periods and 2)- to identify key variables (e.g. GPS data, RPE, training duration) which could affect s-IgA.

Saliva samples of 10 elite professional soccer players were collected a)- before the investigation started to establish the baseline level, b)-before and after each 4 training sessions (LI vs. HI). Training intensity was monitored as internal (via heart rate responses and RPE) and external (via GPS) loads.

HI sessions were associated with higher external load (GPS) and with higher RPE. Baseline and Pre-Training s-IgA did not differ between the 4 training sessions both for HI and LI. Post-Training s-IgA were not different (in absolute value and in percentage of change) between HI and LI sessions at the first three periods. However, at the fourth period, s-IgA concentration for HI session was significantly lower (p<0.05) than the LI session. The percentage change between s-IgA post-training and s-IgA baseline concentrations differ significantly (p<0.05) between HI and LI training sessions. Significant correlations between s-IgA and training intensity were also noted.

HI soccer training sessions might cause a significant decrease in s-IgA values during the post-exercise window as compared with LI sessions. This study encourages coaches to monitor s-IgA in routine particularly during HI training periods to take precautions to avoid upper respiratory tract infection in highly trained soccer players.

Copyright (C) 2015 by the National Strength & Conditioning Association.

An English championship league soccer team did not experience impaired physical match performance in second match after 75 hours of recovery

The purpose of this study was to examine the hormonal and neuromuscular responses and physical match performance in a second match after 75 hours of recovery in English Championship League (ECL) football players during a mid-season weekly period. Nine male professional outfield footballers whose average age, height, and mass were 25.7 years, 180 cm, 78.1 kg respectively from an ECL team competed in two matches separated by 75 hours. The players completed an optional post-match recovery strategy that included: massage, cold-water immersion, or low intensity dynamic movement. Team possession was greater in match two compared to match one (48 to 62%) while average pass frequency by each player increased in match two. High intensity running was significantly greater during the second half of match 2 in comparison to the first half.

Salivary cortisol was significantly elevated immediately post-match one compared to baseline. Jump height was reduced post-match one for up to 40 hours. In conclusion, the ECL football players in this study did not experience impaired physical performance in the second match after 75 hours of recovery, indicating that players coped with this short recovery period between matches. In addition, support for the use of athlete monitoring to assess recovery status is evident since each match elicited different post-match hormonal and neuromuscular responses.

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