‘Climb assist’ claims to reduce strain when climbing ladders; however, no research has yet substantiated this. The purpose of this study was to assess the physiological and psychophysical effects of climb assist on 30 m ladder climbing at a minimum acceptable speed. Eight participants (six male and two female) climbed a 30 m ladder at 24 rungs per minute with and without climb assist, and were monitored for heart rate (HR), O2 and rate of perceived exertion (RPE). All three variables decreased significantly (p < 0.05) with climb assist with O2 decreasing by 22.5%, HR by 14.8% and RPE decreasing by a mean of 2.3 units on the 10-point Borg scale. When descending the ladder O2 decreased by a mean of 42% compared to that ascending. At the minimal acceptable climbing speed climb assist decreases the physiological strain on climbers, as demonstrated by reduced O2, HR and perceived exertion.Practitioner Summary: ‘Climb assist’ systems claim to reduce strain when climbing, however; no research has yet been published to substantiate this. A crossover study compared O2, HR and RPE at a minimal acceptable climbing speed with and without climb assist. Climb assist significantly reduced all variables confirming it reduces strain when climbing.