REF-1632 · Saeterbakken et al., 2022 · Sports Medicine, · Paper · PubMed

Trunk (core) muscle training in competitive athletes, against active controls, raised local muscular endurance a lot (SMD 1.29), sport-specific performance moderately (SMD 0.64) and maximal strength and leg power a little (SMD 0.39 and 0.30), in a meta-analysis of 31 controlled trials with 693 athletes aged 11-37 (PEDro 5); power and sprint gains went with more than 18 sessions, sprint and change-of-direction gains with sessions of 30 min or less

Main caveat: Mostly small trials of middling quality (PEDro 5); confidence intervals and heterogeneity are not in the abstract.
fairly strong evidenceMeasured on trained to highly trained athletesRead from the abstract only

Saeterbakken and colleagues pooled controlled trials that tested trunk muscle training in young and adult competitive athletes and asked what it does to physical fitness and to performance in the athletes' own sport, and which athlete traits and programme settings change the effect.

They searched PubMed, Web of Science and SPORTDiscus up to June 2021 and included 31 studies with 693 participants aged 11-37, compared against active control groups. The authors rate the included studies' methodological quality at 5 on the PEDro scale (the abstract does not say whether this is a mean or a median).

Core training improved every fitness measure pooled: local muscular endurance most (SMD 1.29), then change-of-direction speed (0.70), linear sprint (0.66), maximal strength (0.39) and lower-limb power (0.30); sport-specific performance, such as throwing velocity or swimming time, improved moderately (0.64).

In subgroup analyses the change-of-direction benefit was significant only in children, more than 18 sessions went with larger power and sprint effects, sessions of 30 min or less with large sprint and change-of-direction effects, and sessions over 30 min with a large sport-specific effect.

The authors conclude that core training is an effective way to improve selected fitness and sport measures in athletes.

Participants

31 studies, 693 participants aged 11-37 years.
Competitive athletes at regional, national or international level; the authors class national or international competitors as elite and the rest as regional (recreational and sub-elite).
Sports: several; the abstract's examples are throwing velocity and swimming time, and the PubMed indexing lists swimming. Sex split and the number of studies per sport are not in the abstract.

Methods

Search: PubMed, Web of Science and SPORTDiscus, no date limit, up to June 2021.
Inclusion: controlled trials with baseline and follow-up measures of at least one fitness measure (for example maximal strength, sprint, change-of-direction speed) and a sport-specific performance measure, in competitive athletes.
Quality: PEDro scale; the included studies scored 5.
Analysis: random-effects weighted standardised mean differences (SMD) between training and active control groups; univariate subgroup analyses for age, sex, expertise level, frequency, study length, session duration and number of sessions.
Not in the abstract: which exercises made up the training, what the active controls did, confidence intervals and heterogeneity.

Key Results

Outcome (core training vs active control)SMDSignificant
Local muscular endurance1.29yes
Change-of-direction speed / agility0.70yes
Linear sprint speed0.66yes
Sport-specific performance0.64 (moderate, per the authors)yes
Maximal muscle strength0.39yes
Lower-limb muscle power0.30yes
Age moderated change of direction (p = 0.04): a large effect in children (SMD 1.53, p = 0.002); the authors read the change-of-direction benefit as limited to children.
Number of sessions moderated power and sprint (p ≤ 0.03): with more than 18 sessions the effects were significant, SMD 0.45-0.84 (p ≤ 0.003), against 18 or fewer.
Session duration moderated sprint, change of direction and sport-specific performance (p ≤ 0.05): 30 min or less gave large sprint and change-of-direction effects (SMD 1.66-2.42, p ≤ 0.002); more than 30 min gave a large sport-specific effect (SMD 1.22, p = 0.008).
The abstract reports no subgroup result for sex or expertise level.

Practical Application

Core work is worth a short slot in an athlete's training, mainly for trunk endurance. Across 31 controlled trials in competitive athletes it lifted local muscular endurance most (SMD 1.29) and sport-specific performance moderately (0.64) beyond what the active controls gained; maximal strength and leg power moved only a little (0.39 and 0.30).
Short sessions were enough for speed. Sessions of 30 min or less went with the large sprint and change-of-direction effects, and programmes of more than 18 sessions with the power and sprint gains; sessions over 30 min, though, went with the large sport-specific effect (SMD 1.22), so short sessions are not shown to be better for sport performance.
Inference, not tested here: for a runner, cyclist or triathlete, a short core block attached to existing strength sessions builds up that session count over a normal training block without taking ride or run time; heavy lower-body lifting stays the strength priority in the base (SYNTH-44).
The change-of-direction result belongs to children. It was significant only in the child subgroup, so it says little about adult endurance athletes.
Not settled by this design: whether core training makes an endurance athlete faster. The abstract pools all sports into one sport-specific estimate and gives no running, cycling or triathlon figure; in male college athletes from mixed sports, core training did not improve running economy against a control group (REF-1019), and the injury evidence is mixed (REF-1384, REF-1244).

Limitations

Mostly small trials of middling quality (PEDro 5); confidence intervals and heterogeneity are not in the abstract.
Controlled trials, not all stated to be randomised.
Ages 11-37 and many sports pooled; children carry the change-of-direction effect, and no endurance-sport estimate is given.
The dose findings are univariate subgroup comparisons between studies: they show which programmes went with larger effects, not that the dose caused them.
The exercises used and the control conditions are not described in the abstract.
Written from the abstract and the PubMed record; full text not read.
How this entry was checked and changed
Why this level

a meta-analysis of controlled trials whose abstract reports its quality appraisal and the result (PEDro 5, a middling score on that scale), so the abstract-only cap does not apply; held at A- because the trials are mostly small (693 participants across 31 studies, about 22 per study by our arithmetic), not all are stated to be randomised, and the dose findings are univariate subgroup splits; confidence intervals and heterogeneity are not in the abstract

Content correction 2026-11-07
2026-11-07: added from the abstract and the PubMed record; level A- (meta-analysis of mostly small controlled trials, PEDro 5 reported in the abstract).