Fig 1.
Schematic flowchart of study selection from initial search to the final study inclusion.
Fig 2.
Summary of included experimental groups with forest plot for low (a), moderate (b) and high (c) clusters. QA: Quality assessment; EIMD: exercise-induced muscle damage; Sed: Sedentary; Act: Active; Train: trained;?: unknown; ECCiso: eccentric contractions using an isokinetic ergometer; Plyo: Plyometric exercise; Resist: Eccentric/resistance exercises; DW/R: downhill walking/running; Prol: prolonged aerobic exercise; NM-ES: Neuromuscular electrostimulation; CK: creatine kinase; DOMS: delayed-onset muscle damage; Mb: myoglobin; ROM: range of motion; JH: jump height; EV: evoked response; PPT: pain pressure threshold; VAL: voluntary activation level; LDH: lactate dehydrogenase; RTD: rate of torque development; LC: limb circumference; IL-6: iterleukin-6; T2: transverse relaxation time. “n” represents the number of participants of the experimental group. Data are displayed as standard mean difference (SMD) ± standard error.
Table 1.
LOW, MOD and HIGH clusters’ characteristics.
Distribution of training status (a), exercise modality (b) and exercise type (c). Data are expressed in percentage of total participants (%). Expected values corresponds to the distribution of each characteristic in the whole sample. ECCiso: eccentric contractions using an isokinetic ergometer; Plyo: Plyometric exercise; Resist: eccentric/resistance exercises; DW/R: downhill walking/running; Prol: prolonged aerobic exercise; NM-ES: Neuromuscular electrostimulation. Any significant association between clusters and characteristics are displayed (*: p < 0.05; **: p < 0.01).
Table 2.
Coefficient of determination (r2) and p-value of meta-regressions between peak reductions in maximal voluntary contraction (MVC) torque and changes in jump height, range of motion, active DOMS, passive DOMS, pain pressure threshold (PPT), limb circumference, evoked response, rate of torque development (RTD), voluntary activation level (VAL), creatine kinase (CK), myoglobin (Mb), lactate dehydrogenase (LDH), interleukin-6 (IL-6) and transverse relaxation time (T2).
“n” represents the number of studies included in the analysis. Results with a P-value < 0.05 are considered significant and are displayed in bold characters.
Fig 3.
Time-course changes in pain pressure threshold (PPT), limb circumference, rate of torque development (RTD), voluntary activation level (VAL), lactate dehydrogenase (LDH), interleukin-6 (IL-6) and transverse relaxation time (T2) at < 6 h, 24h, 48h, 72h and > 96 h post-exercise.
The number in parenthesis represents the number of studies. Data are displayed as mean of standard mean difference (SMD) ± standard error. *: Significant difference from baseline at p < 0.05; *: **: Significant difference from baseline at p < 0.01; ***: Significant difference from baseline at p < 0.001.
Fig 4.
Time-course changes in maximal voluntary contraction torque (a-b), evoked response (c-d), jump height (e-f), and range of motion (g-h) after exercise. Standard mean difference (SMD) and standard error were displayed for all included groups (a, c, e, g) and for three clusters representing three levels of maximal voluntary contraction torque loss (b, d, f, h). The number in parenthesis represents the number of studies. Significant differences from baseline (before the damaging exercise) were displayed: *: p < 0.05; **: p < 0.01; ***; p < 0.001; ns: non-significant.
Fig 5.
Time-course changes in active DOMS (a-b), passive DOMS (c-d), creatine kinase (e-f), and myoglobin (g-h). Standard mean difference (SMD) and standard error were displayed for all included groups (a, c, e, g) and for three clusters representing three levels of maximal voluntary contraction torque loss (b, d, f, h). The number in parenthesis represents the number of studies included in the analysis. Significant differences from baseline (before the damaging exercise) were displayed: *: p < 0.05; **: p < 0.01; ***; p < 0.001; ns: non-significant.