McFarlin 2016.

Methods	Randomised controlled trial (parallel design)
Participants	Setting: laboratory; USA n = 28 participants (40 in all) Mean age curcumin group (n = 16, 11 females) 20 (SD 1) years Mean age placebo group (n = 12, 7 females) 19 (SD 2) years "We experienced a 30% attrition/non‐compliance"; it was not specified which group these participants withdrew from. Inclusion/exclusion criteria Exclusion criteria included regular resistance training in the previous 6 months, leg muscle or orthopaedic condition, arthritis or other chronic inflammatory injury in the lower extremity, regular ingestion of curcumin containing foods, regular anti‐inflammatory use, intake of curcumin supplementation in the pas 6 months and any other condition that would prohibit the completion of the lower body resistance exercise protocol
Interventions	Intervention Curcumin supplementation (Longvida; Verdure Sciences Corp, Noblesville, IN) 400 mg per dose; total study dose 2400 mg Placebo 400 mg rice flour Duration 2 days prior to exercise, the day of and 3 days after exercise, total duration of 6 days
Outcomes	PRIMARY Soreness was measured using a 10 cm visual analogue scale from 0 at one end "no pain" to 10 "severe pain" at the other end. Measures of soreness were made on the thigh (i.e. quadriceps). A gauge was applied using standard fore (20 to 30 N) over the distal, middle and proximal thigh in a seated position with the knee fully extended and relaxed. The 3 ratings for each quadricep were added together
Exercise type	6 sets of 10 repetition of the leg press exercise with a start load set at 110% of the estimated 1 repetition maximum
Sources of funding	The study was partially funded by a grant from Verdure Sciences Corp (PI: McFarlin) and the National Strength and Conditioning Association to the University of North Texas
Notes	Authors contacted on 4 February 2017 to request data for delayed onset muscle soreness but no reply was received
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Manuscript states: "Stratified randomization (based on gender and initial strength) was used to assign participants to the treatment conditions to ensure similar numbers of men and women and a balance based on initial muscle strength between conditions"
Allocation concealment (selection bias)	Unclear risk	No specific details provided on how randomisation was completed Authors contacted on 4 February 2017 but no reply was received
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Manuscript states: "Subjects were provided supplements using a double‐blind approach". However, no specific details were provided. Authors contacted on 4 February 2017 but no reply was received
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Double‐blind
Incomplete outcome data (attrition bias) All outcomes	High risk	Manuscript states: "we enrolled 20 subjects per group" and "In the case of the present study, no subjects asked to drop (sic), thus the key source of attrition was associated with lack of adherence to the study protocol or sample collection." This equates to 30% data loss and there was an uneven dropout rate between groups.
Selective reporting (reporting bias)	High risk	No published protocol available All outcomes reported at all time points Adverse effects of antioxidant supplementation were not reported
Other bias	Low risk	Manuscript states: "Exclusion criteria included: regular resistance training in the previous 6 months, leg muscle or orthopedic condition, arthritis or other chronic inflammatory injury in the lower extremity, regular ingestion (N2 times per week) of curcumin containing foods, regular NSAID use (at least 3 of 7 days), intake of a curcumin supplement (within the past 6 months), and any other condition that would prohibit completion of the lower body resistance exercise protocol"