Table 2. GRADE summary of evidence.
| Certainty assessment | No of patients | Effect | Certainty | Importance | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| No of studies | Study design | Risk of bias | Inconsistency | Indirectness | Imprecision | Other considerations | (EXP) | (CON) | Relative (95% CI) |
Absolute (95% CI) |
||
| Body composition | ||||||||||||
| 24 | RT | Seriousa | Seriousb | Not serious | Not serious | None | 322 | 314 | – | SMD 0.66 SD lower (0.91 lower to 0.41 lower) |
⊕⊕〇〇 Lowa,b |
IMPORTANT |
| Change of direction ability | ||||||||||||
| 5 | RT | Seriousa | Not serious | Not serious | Seriousc | None | 59 | 55 | – | MD 0.27 s lower (0.41 lower to 0.13 lower) |
⊕⊕〇〇 Lowa,c |
IMPORTANT |
| Aerobic capacity | ||||||||||||
| 13 | RT | Seriousa | Very seriousd | Not serious | Not serious | None | 213 | 201 | – | MD 3.66 ml/kg/min higher (2.67 higher to 4.65 higher) |
⊕〇〇〇 Very lowa,d |
CRITICAL |
| Anaerobic capacity | ||||||||||||
| 8 | RT | Seriousa | Not serious | Not serious | Seriouse | None | 62 | 86 | – | MD 37.36 W higher (22.3 higher to 52.42 higher) |
⊕⊕〇〇 Lowa,e |
CRITICAL |
| Sprint ability | ||||||||||||
| 12 | RT | Seriousa | Seriousf | Not serious | Not serious | None | 133 | 110 | – | MD 0.17 s lower (0.24 lower to 0.11 lower) |
⊕⊕〇〇 Lowa,f |
IMPORTANT |
| Explosive power | ||||||||||||
| 17 | RT | Seriousa | Not serious | Not serious | Not serious | None | 233 | 206 | – | MD 1.55 cm higher (1.16 higher to 1.95 higher) |
⊕⊕⊕〇 Moderatea |
CRITICAL |
Note:
RT, randomised trials; CI, confidence interval; MD, mean difference; SMD, standardised mean difference; a, Most studies lacked allocation concealment or blinding; b, I2 = 55.9%; c, Only 5 RCTs were included; d, I2 = 82.4%; e, Only 8 RCTs were included; f, I2 = 48.5%; Risk of bias includes issues such as incorrect randomization, lack of allocation concealment, absence of blinding, excessive loss to follow-up, selective outcome reporting, or early termination of the study after observing a beneficial effect. If most of the studies exhibit one or more important risks of bias, the quality of evidence should be downgraded by one level; Inconsistency refers to considerable heterogeneity among studies or a very low p-value in heterogeneity tests. When substantial and unexplained inconsistency is present, the quality of evidence should be downgraded by one level. Indirectness arises when the patients, interventions, comparisons, or outcome measures in the available studies differ from the target PICO elements specified in the review question. If an important degree of indirectness exists, the quality of evidence should be downgraded by one level. Imprecision includes situations with a small sample size, a limited number of included studies, or confidence intervals that include the line of no effect. When evidence is uncertain due to an insufficient sample size or number of events, the quality of evidence should be downgraded by one level. Other considerations include publication bias, a large magnitude of effect, or a dose-response gradient. If there is a strong suspicion of publication bias, the quality of evidence should be downgraded by one level.