Immune inflammation markers and physical fitness during a congested match play period in elite male soccer players

Abstract

Background/objective: Cellular immune markers of inflammation such as neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR) and systemic immune inflammation index (SII) are frequently used in patient care. The adoption of these markers to elite sports, e.g. soccer could be beneficial when monitoring training and aiming to maximize physical fitness. This study investigated cellular immune inflammation markers and physical fitness in elite male soccer players in relation to changes in training and match exposure during a congested match play period.

Methods: Fifteen elite male soccer players were evaluated three times (T1, T2, and T3) over 12 weeks (T1-T2: six weeks uncongested period of match play and T2-T3: six weeks congested period of match play). Players performed vertical jump tests (squat jumps [SJ], countermovement jumps [CMJ]), the 20-meter sprint test, and the Yo-Yo intermittent recovery test (YYIRL1) at T1, T2 and T3. Measurements included counts of leucocytes and its subtypes, as well as platelets. Cellular immune inflammation markers (NLR, PLR and SII) were calculatedat T1, T2, and T3. Training session rating of perceived exertion was also recorded on a daily basis.

Results: Significant increases in leucocyte, neutrophil, eosinophil, basophil and monocyte counts occurred at T3 compared with T2 (0.002 < p < 0.04, -0.56 < ES < -0.40) and T1 (-0.78 < ES < -0.49). Lymphocyte counts were lower at T3 as compared to T2 and T1 (p = 0.038, -0.48 < ES <-0.25), while NLR, PLR and SII were greater at T3 compared to T2 (0.001 < p < 0.015, -1.01 < ES < -0.44) and T1 (-0.99 < ES < -0.21). There was a negative correlation between YYIRL1 performance with NLR (r= -0.56; p = 0.02), PLR (r=-0,44, p = 0.015), and SII (r= -0.63; p = 0.01) after the congested period of match play (i.e., T3). Values for maximal oxygen uptake (VO_2max), estimated from the YYIRL1 test, negatively correlated with NLR (r= -0.56; p = 0.02), PLR (r=-0,44, p = 0.015), and SII (p = 0.01; r= -0.63). There was a positive correlation between NLR, and SII with workload parameters. In addition, a clear positive correlation was observed between NLR and SII with competitive loadinstead (r= [0.59-0.64; p˂ 0.001), training load (TL) (r= [0.65-0.68]; p˂ 0.001), session rating of perceived exertion (S-RPE) (r= [0.65-0.68]; p = 0.001), and training volume (r= [0.60-0.61; p = 0.001).

Conclusion: An intensive period of congested match play significantly alterated immune cell counts and cellular markers of inflammation (NLR, PLR and SII). Changes in NLR and SII were related to workload parameters, suggesting the usefulness of these markers in regulating training intensity and competitive load. An association between physical fitness (YYIRL1, VO_2max) and NLR, PLR and SII suggests that these biomarkers are promising tools to monitor aerobic physical fitness of elite soccer players during congested periods of match play.

Keywords: Congested calendar; Integrative immune markers; Overtraining; Soccer; White blood cells.

Fig. 1

Experimental design. Abbreviations: W, week; BS, blood sample; CMJ, countermovement jump; YYIRL1, Yo-Yo intermittent recovery test-level 1; Sun, Sunday; Mon, Monday; Tue, Tuesday; Wed, Wednesday; Thu, Thursday; Fri, Friday; Sat, Saturday; Sun, Sunday; RPE, rating of perceived exertion; SP, sprint; SJ, squat jump.

Fig. 2

Team measures of global load parameters during the uncongested and congested periods of match play. Abbreviations: AU, arbitrary units. *significant difference between uncongested and congested periods.

Fig. 3

Team and individual values of workload parameters during the uncongested and congested periods. Abbreviations: A.U, Arbitrary units, S-RPE: session rating of perceived excertion. TL: training load, CL, Competitive load. Black dots and lines represent team mean values ± 95% confidence interval of different workload parameters during the uncongested and congested periods. Grey dots represent changes in individual values for different workload parameters during the uncongested and congested periods.

Fig. 4

Weekly total load, competitive load, training load and S-RPE and training volume during the uncongested and congested periods. Abbreviations: A.U, arbitrary units, S-RPE: session rating of perceived exertion. Training Load (A.U) = S-RPE (A.U) × training volume (min).

Fig. 5

Team and individual values of physical fitness measures during the competitive periods. Abbreviation CMJ, countermovement jump; SJ, squat jump; VO_2max, maximal oxygen consumption; YYIR1, Yo-Yo Intermittent Recovery Test Level 1. T1, before the uncongested period; T2, after the uncongested period (before the congested period); T3, after the congested period. Black dots and lines represent team mean values ± 95% confidence interval for physical fitness measures during the competitive periods. Grey dots represent changes in individual values for physical fitness during the competitive periods.

Fig. 6

Team and individual values of cellular immune inflammation markers during the competitive periods. Abbreviations: A.U, Arbitrary units, NLR, neutrophil-to-lymphocyte ratio; PLR, platelet-to-lymphocyte ratio; SII, systemic immune inflammation index. T1, before the uncongested period; T2, after the uncongested period (before the congested period); T3, after the congested period. Black dots and lines represent team mean values ± 95% confidence interval of different immune inflammation markers during the competitive periods. Grey dots represent changes in individual values for different immune inflammation markers.

Fig. 7

Associations between NLR with VO_2max and YYIRL1 performance during the congested period. Abbreviations: NLR, neutrophil-to-lymphocyte ratio; VO_2max, maximal oxygen consumption; YYIR1, Yo-Yo Intermittent Recovery Test Level 1.

Fig. 8

Associations between SSI with VO_2max and YYIRL1 performance during the congested period. Abbreviations: SII, systemic immune inflammation index; VO_2max, maximal oxygen consumption; YYIR1, Yo-Yo Intermittent Recovery Test Level 1.