Weir 2011.

Methods	Study design: single‐blinded randomized controlled trial Setting: The Hague Medical Centre, Antoniushove hospital, Department of Sports Medicine. Leidschendam, the Netherlands
Participants	N = 54 (exercise therapy group, n = 25; multi‐modal treatment group, n = 29) Athletes Age range: 18 to 50 years Gender: 53 male/1 female Groin pain during and after sporting activities for at least 2 months Desire to return to active sports participation at pre injury level Pain located at the proximal insertion of adductor muscles on the pubic bone, and during active adduction against resistance
Interventions	1. Multi‐modal treatment group (MMT): heat + manual therapy + stretching. ‐ Maximum two sessions of manual therapy and heat, and 15 days of stretching (the stretches were done after a 5 min warming‐up using jogging or cycling). Before the manual therapy the adductor muscle group is warmed using paraffin packs for 10 min ‐ The manual therapy technique consists of: with the patient in a supine position, the contralateral hand is used to control the tension in the adductor muscles while the ipsilateral hand is used to move the hip from a neutral position into flexion, external rotation and abduction while keeping the knee in extension. The treating physician controls the tension subjectively and applies the maximum tolerable stretch to the adductor muscles. After the movement has been performed the adductor muscle group is compressed with one hand while the other hand moves the hip into adduction and slight flexion. This circular motion followed by compressions lasts about 25 s and is repeated three times in one treatment session 2. Exercise therapy group (ET): 8 to 12 weeks; 3 times a week. Module 1: first 2 weeks ‐ Static adduction against soccer ball placed between feet when lying supine (10 rep. of 30s, each) ‐ Static adduction against soccer ball placed between knees when lying supine (10 rep. of 30s, each) ‐ Abdominal sit‐ups both in straightforward direction and in oblique direction (5 series of 10 rep.) ‐ Combined abdominal sit‐ups and hip flexion, starting from supine position and with soccer ball between knees (5 series of 10 rep.) ‐ Balance training on wobble board (5 min) ‐ One‐foot exercises on sliding board, with parallel feet as well as with 90 angle between feet (5 sets of 1 min continuous work with each leg and in both positions)   Module 2: 2 to 6 weeks ‐ Leg abduction and adduction exercises performed in side lying (5 series of 10 rep. of each exercise‐ twice) ‐ Low‐back extension exercises prone over end of couch (5 series of 10 rep. – twice) ‐ One‐leg weight pulling abduction/adduction standing (5 series of 10 rep. for each leg – twice) ‐ Abdominal sit‐ups both in straightforward direction and in oblique direction (5 series of 10 rep. – twice) ‐ One‐leg coordination exercise with flexing and extending knee and swinging arms in same rhythm(5 series of 10 rep. for each leg – twice) ‐ Training in sideways motion on mini‐skateboard (5 min) ‐ Balance training on wobble board (5 min) ‐ Skating movements on sliding board (5 sets of 1 min continuous work) In both groups a return to running program was done after treatment.
Outcomes	Successful treatment: ‐ No pain in connection with or after athletic activity in the same sport and at the same level of competition ‐ No pain during resisted adduction or on palpation of the adductors tendon at the pubic bone insertion ‐ Return to sports at the same level without groin pain If all three measures above were reached, the result was labelled excellent, if two measures were reached, the result was good, if one measure was reached, the result was fair and if no measures were reached, the result was poor. Maximum pain during sports (Visual analogue scores, 0‐100) Time to return to sports Range of motion of the hip joint (internal and external rotation): It was used a goniometer with the patients lying and the hip and knee flexed to 90º Outcomes were evaluated at 16 weeks follow‐up.
Notes	The participants from exercise therapy (ET) were not supervised while performed the exercises. They were only instructed on how to perform it. Percentage of participants lost to follow‐up: 11% (6/59); 3 losses from ET group and 3 from MMT group Reasons for withdrawal: did not want the treatment they were assigned (three patients); ankle injury (one patient); low‐back pain (one patients); and lost to follow‐up (one patient)
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "After informed consent and inclusion the athletes were randomised using sealed envelopes.The athlete chose one of 100 opaque envelopes in the presence of the department’s secretary"
Allocation concealment (selection bias)	Low risk	Quote: "After informed consent and inclusion the athletes were randomised using sealed envelopes.The athlete chose one of 100 opaque envelopes in the presence of the department’s secretary" Quote: "The examining physician was not involved in the randomisation process and remained unaware of the treatment allocation"
Blinding of participants and personnel (performance bias) All outcomes	High risk	Participants and physiotherapists could not be blinded to allocation treatment
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	While the examining physician was not involved in the randomization procedure and remained unaware of the treatment allocation, there were subjective outcomes (Successful treatment) assessed by the trial participants, who were not blinded
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Although missing data were balanced across groups and reasons for missing data were provided, the characteristics of the lost participants were not described. Furthermore, a per protocol analysis was done
Selective reporting (reporting bias)	Unclear risk	Function (an important primary outcome) was not evaluated. No protocol available
Other bias	Low risk	No other source of bias was detected

rep. = repetitions