The Biomechanics of the Kinetic Chain
Every powerful serve or lightning-fast volley in a racket sport is the result of a complex sequence of movements known as the kinetic chain. This framework describes how the body functions as a system of linked segments: force generated by the legs travels through the trunk and is finally delivered through the arm and racket. At the center of this chain lies the core — the muscles of the abdomen, pelvis, lower back, and hips — acting not just as a source of power, but as the body's central stabilizer and force-transducer [1, 2].
When an athlete possesses a strong, stable midsection, they achieve what biomechanists call proximal stability: a solid foundation that allows for greater mobility and power in the arms and legs. Without this central rigidity, energy "leaks" through the torso, forcing the smaller muscles of the shoulder and elbow to overcompensate. This doesn't just reduce power — it also elevates injury risk, particularly in the shoulders, elbows, and spine [1, 3]. This is why the core matters for longevity, not just performance.
A comprehensive new meta-analysis by Yu et al. [1] synthesized data from 18 randomized controlled trials to quantify how core strength training (CST) transforms these biomechanical principles into measurable gains on court. The results confirm that CST significantly improves core endurance, agility, balance, stability, and muscular strength, while also enhancing technical skills like ball velocity and accuracy. But as we'll see, some of these benefits are supported by stronger evidence than others.
Inside the Research
The meta-analysis by Yu et al. followed PRISMA guidelines and drew from four major databases — Web of Science, Scopus, SportDiscus, and PubMed — screening 514 initial records down to 18 randomized controlled trials that met strict inclusion criteria. Every included study had to isolate core strength training as the sole intervention (no combined programs with nutrition or sleep management), run for at least four weeks, and compare against a control group receiving either regular training, traditional strength work, or no additional training. This design lets us attribute observed changes to core training itself rather than other variables.
The 18 studies spanned nine countries, with the majority conducted in China and Turkey. Eleven focused on tennis players, four on badminton athletes, and two on table tennis players. Participants ranged from adolescents as young as 12 to collegiate athletes in their mid-twenties, and sample sizes were generally small — from 12 to 40 per study, with a median of 26. Most training programs used a combination of static and dynamic core exercises (think planks, medicine ball throws, and rotational movements) performed two to three times per week for sessions lasting 20 to 60 minutes.
To gauge the physical effects, researchers used a variety of validated tests. Agility was typically assessed with the Pro-Agility Test, a standard drill requiring athletes to sprint, plant, and change direction as fast as possible. Balance was most commonly measured using the Star Excursion Balance Test (SEBT), where athletes stand on one leg and reach as far as they can in multiple directions — a task that closely mirrors the single-leg demands of lunging for a drop shot or stretching for a wide volley. Other studies used the Flamingo Balance Test or eyes-closed standing tests. Core stability was assessed through challenges like the Grade VIII abdominal bridge, a progressively harder series of plank-based holds, and timed supine leg-lift holds. Core endurance was measured with timed tests such as the abdominal fatigue test and supine back extension — how long you can hold under sustained trunk load.
For technical performance, the researchers tracked ball velocity via radar-gun readings of serve and smash speeds, ball accuracy through targeted placement tests across various stroke types (forehand, backhand, cross-court, down-the-line), and spin control through sport-specific assessments of an athlete's ability to generate and regulate ball rotation.
What the Numbers Actually Show
What makes this meta-analysis particularly valuable is that it moves beyond general claims and provides pooled effect sizes — a standardized way of measuring how large a training effect truly is. In exercise science, a Cohen's d of 0.2 is considered a small effect, 0.5 is medium, and 0.8 or above is large.
The strongest and most consistent finding was for agility. Across the studies, CST produced a large pooled effect (d = 1.22), and critically, heterogeneity was zero — meaning every study pointed in the same direction regardless of the specific sport, age group, or training protocol. For coaches, this is the headline result: core training reliably and substantially improves the rapid, multi-directional bursts of speed that racket sports demand.
Core stability also showed a large effect (d = 1.87), and balance came in at d = 1.16. However, both of these outcomes had high heterogeneity (I² = 91% and 71% respectively after sensitivity analysis), meaning the size of the benefit varied quite a bit between studies. Some athletes saw dramatic gains; others, more modest ones. Factors like baseline fitness, age, and the specific exercises used likely explain these differences. The takeaway is that CST almost certainly improves stability and balance, but the magnitude you can expect depends on your starting point and program design.
On the technical side, CST produced a moderate effect on ball velocity (d = 0.57) with zero heterogeneity — a consistent but more modest gain. This makes biomechanical sense: the core is a "force bridge" in the kinetic chain, and a stronger bridge means more efficient energy transfer from legs to racket, but it is just one link in that chain. Improvements in ball accuracy and spin control were also consistently reported across studies, though these outcomes couldn't be formally pooled in the meta-analysis due to differences in how they were measured. All relevant studies did report significant improvements, which is encouraging but should be interpreted as preliminary rather than definitive.
It's worth noting where the evidence was more mixed. Flexibility results were inconsistent: one study found significant improvement while another did not, likely reflecting that standard core exercises don't provide the same stimulus as dedicated stretching. Lower-body strength showed a similar split — two of three studies found gains, but one using a squat test found no significant difference. This makes sense because CST primarily targets the lumbar-pelvic-hip complex rather than directly loading the legs, so any lower-body benefits are indirect. Core endurance, however, was consistently improved across all three studies that assessed it — a finding that matters for match fitness, since endurance of the trunk muscles is what allows athletes to maintain proper stroke mechanics deep into a gruelling third set.
The evidence base itself has some important context. Of the 18 studies, 11 focused on tennis, four on badminton, and two on table tennis — so the findings are most directly applicable to tennis players, though the shared biomechanical demands across racket sports make reasonable generalization possible. Sample sizes were generally small (median of 26 participants, smallest just 12), and methodological quality was moderate: PEDro scores ranged from 4 to 7 out of 10, with only one study implementing blinding of participants. These are common limitations in exercise science research, and the consistency of positive results across studies of varying quality is reassuring, but it does mean the precise effect sizes should be treated as useful estimates rather than exact predictions.
Practical Programming for Performance
Translating these findings into a training routine requires thinking about how the trunk actually functions during play. Programming should prioritize proximal stability — building a stiff, resilient midsection that enables more powerful and precise movements in the arms and legs.
Based on the meta-analysis, the most effective protocols used two to three sessions per week for a minimum of four to eight weeks, integrated alongside regular sport-specific training [1]. Exercise selection should progress from static stability to dynamic, high-velocity movements. An athlete might begin with isometric exercises like planks or Pallof presses to build foundational tension, then transition to rotational power movements such as medicine ball throws or cable rotations that more closely mimic the unilateral nature of racket swings.
Crucially, the training must account for the multi-planar nature of these sports. While traditional abdominal work often focuses on the sagittal plane (forward and backward movement), racket sports occur primarily in the frontal and transverse planes. Programming should therefore emphasize lateral stability and rotational control — movements that protect the spine while enhancing the trunk rotation that drives shot power [2, 4].
One of the review's most practical insights is that CST combined with sport-specific skill training appears to yield greater technical improvements than either approach alone [1]. For shot accuracy and spin control in particular, pairing core conditioning with on-court drill work that targets racket face control, timing, and stroke variability is likely the most effective strategy. For younger athletes, CST supports motor coordination and foundational movement quality, while for more advanced players, the focus shifts toward stroke efficiency and injury prevention — an especially relevant benefit given the shoulder, elbow, and spinal stress that competitive racket sports impose [5].
References
- Yu X., Yin H. & Zhang J. "Effectiveness of core strength training for racket sport athletes' performance: a systematic review and meta-analysis", Scientific Reports (2026). https://doi.org/10.1038/s41598-026-39391-w
- Kibler W.B., Press J. & Sciascia A. "The Role of Core Stability in Athletic Function", Sports Medicine 36 (2006) 189–198. https://doi.org/10.2165/00007256-200636030-00001
- Rodríguez-Perea Á. et al. "Core training and performance: a systematic review with meta-analysis", Biology of Sport 40 (2023) 975–992. https://doi.org/10.5114/biolsport.2023.123319
- Huxel Bliven K.C. & Anderson B.E. "Core Stability Training for Injury Prevention", Sports Health 5 (2013) 514–522. https://doi.org/10.1177/1941738113481200
- McGill S. "Core training: Evidence translating to better performance and injury prevention", Strength and Conditioning Journal 32 (2010) 33–46. https://doi.org/10.1519/SSC.0b013e3181df4521