Table 1.

Characteristics of included studies and intervention

Study	Participants	Interventions	Outcome (follow-up time): statistical significance	Baseline differences
Dziedzic et al. (2015) [27]	RGb = 65 CGb = 65 N = 104 66% F 66 (9.1) years old	RG (n = 55): supervision = 1 group session/week (for 4 weeks). exercise = elastic bands fingers e/f, Play-Doh finger e/f (? % MVC), 0.5–0.75 kg wrist e/f dosage = 3 reps/day, every day progression = up to 10 reps/day CG (n = 49): leaflet and advice (extensive information)	Grip strength (24 wks): NS AUSCAN pain (12 wks): NS AUSCAN function (12 wks): NS	Strength (p = ?) Pain (p = 0.6) Function (p = 0.5)
Hennig et al. (2015) [31]	RGb = 40 CGb = 40 N = 71 100% F 60.8 (7) years old	RG (n = 37): supervision = 1 individual session with 8 follow-up calls exercise = elastic bands e/a thumb, rubber ball for grip strength (100% MVC) dosage = 10 reps (weeks 1 and 2), 3 days/week progression = 12 reps (weeks 3 and 4), 15 reps (weeks 5–12), 3 days/week CG (n = 34): leaflet and advice (limited information)	Grip strength (12 wks): S NRS pain (12 wks): S FIHOA (12 wks): S	Strength (p = 0.4) Pain (p = ?) Function (p = ?)
Lefler and Armstrong (2004) [28]	RGb = ? CGb = ? N = 19 90% F 81 (9) years old	RG (n = 9): supervised = every session (for 6 weeks); exercise = pinch grip lifting (isometric, 6-sec holds), wrist rolls (isotonic) (MVC = 40%) dosage = 10 reps, 3 days/week progression = up to 15 reps at 60% MVC isometric, 6–8 reps more than 60% MVC isotonic CG (n = 10): no intervention	Grip strength (6 wks): S Likert pain scale (6 wks): NS	Strength (p = 0.08) Pain (p = 0.53)
Østerås et al. (2014) [29]	RGb = 65 CGb = 65 N = 120 90% F 66 (9) years old	RG (n = 57): supervised = 4 group sessions (weeks 1–3 and 8) exercise = shoulder e/f, biceps curl, elastic band e/a thumb, pipe squeeze (100% MVC) dosage = 10 reps, moderate/vigorous intensity (weeks 1 and 2), 3 days/week progression = 15 reps (weeks 3–12) CG (n = 63): usual care (GP visit)	Grip strength (12 wks): NS NRS pain (12 wks): S FIHOA (12 wks): NS	Strength (p = 0.3) Pain (p = 0.4) Function (p = 0.26)
Rogers and Wilder (2009)a [30]	RGb = 76 CGb = 76 N = 46 87% F 75 (6.7) years old	RG (n = 46): supervised = 1 individual session exercise = gripping (16–19% MVC), key pinch, fingertip pinch all with rubber ball dosage = 10 reps (weeks 1, 2, 3 and 4), every day progression = 12 reps, 15 reps, 20 reps all increased every fourth week CG (n = 46): sham hand moisturiser	Grip strength (16 wks): NS AUSCAN pain (16 wks): NS AUSCAN function (16 wks): NS	Strength (p = 0.96) Pain (p = 0.84) Function (p = 0.87)

RGb participants allocated to the resistance training group, CGb participants allocated to the control group, N participants retained at follow-up, F female, RG resistance training group, n group sample size retained at follow-up, wks weeks, e/f extension/flexion, MVC maximum voluntary contraction, ? unable to calculate/unknown, reps repetitions, CG control group, AUSCAN Australian Canadian Osteoarthritis Hand Index, NS nonsignificant, e/a extension/abduction, NRS Numerical Rating Scale, FIHOA Functional Index of Hand Osteoarthritis, S significant

^aCross-over study design