Effectiveness Analysis of Active Stretching Versus Active Stretching Plus Low-Frequency Electrical Stimulation in Children Who Play Soccer and Who Have the Short Hamstring Syndrome.

OBJECTIVE: To determine the effectiveness of active stretching (AS) versus AS plus electrical stimulation (stretching + TENS) in young soccer players with the short hamstring syndrome (SHS).

DESIGN: Randomized, controlled, single-blind parallel clinical trial with 3 arms and a 2-month follow-up. The assignment ratio was 1:1:1.

SETTING: The study involved young federated soccer players in the town of Jumilla, in the region of Murcia (Spain), who were controlled in a physiotherapy office in 2012.

PARTICIPANTS: Fifty-one young soccer players (10-16 years) with SHS.

INTERVENTIONS: Stretching + TENS, AS, and conventional stretching.

MAIN OUTCOME MEASURES: Straight leg raise (SLR) test, popliteal angle with the passive knee extension (PKE) test, and the toe-touch test (TT).

RESULTS: Significant results (P < 0.05) were group 1 versus 2: (1) SLR, -5.5 degrees right; (2) PKE, +10.2 degrees right and +6.2 degrees left; and (3) range of values of clinically relevant parameters (RVCRP): relative risk (RR), 0.35 to 0.38; relative risk reduction (RRR), 0.62 to 0.65; absolute risk reduction (ARR), 0.32 to 0.39; number needed to treat (NNT), 3 to 4. Group 1 versus 3: (1) SLR, -12.3 degrees right and -10 degrees left; (2) PKE, +12.9 degrees right and +8.5 degrees left; (3) TT, -8.9 cm; and (4) RVCRP: RR, 0.12 to 0.28; RRR, 0.72 to 0.88; ARR, 0.60 to 0.83; NNT, 2 to 2. Group 2 versus 3: (1) SLR, -6.8 degrees right and -6.2 degrees left; (2) TT, -6.7 cm; (3) RVCRP: RR, 0.44 to 0.53; RRR, 0.47 to 0.56; ARR, 0.40 to 0.56; NNT, 2 to 3.

CONCLUSIONS: Stretching + TENS produces greater improvement than AS alone, and these are both better than conventional stretching.

CLINICAL RELEVANCE: The use of electrical stimulation combined with AS is a relevant technique for habitual clinical practice that should be systematically integrated in children aged 10 to 16 years who play soccer and who have the SHS.