Maximum voluntary force (MVF) exerted by thumb adduction (TA) declines with skin cooling, with greater decrements in post- menopausal vs. pre-menopausal women1. TA MVF is affected by the menstrual cycle, with increases of ~10% during the follicular stage when oestrogen levels rise2, although similar effects were not observed in handgrip strength3. Intrinsic hand and forearm muscles contribute to handgrip strength, which declines when both are cooled4. However, the effect of hand cooling alone has not been reported. The aim of this study was to determine the effect of hand cooling on TA and handgrip strength during the menstrual cycle. We hypothesised that: i) hand cooling would reduce TA MVF to a greater extent than handgrip; ii) cooling effects are greater when oestrogen levels are lower. 17 healthy women (18-42 yrs) with regular menstrual bleeds not using hormonal contraception, volunteered to attend twice: 7-10 days after the start of the menstrual cycle when oestrogen levels are high, and after the luteinizing hormone peak, when oestrogen levels are low. The hand was cooled and warmed (skin temperatures 12-40oC) in a water bath. TA MVF and maximal handgrip strength were measured at 4-minute intervals and normalised to the subject’s mean at skin temperatures >35oC. A 2-way rANOVA was used to determine the effect of temperature and menstrual status. Post-hoc t-tests were performed across temperature bins. A-priori power calculation suggests a sample size of 40 is required to establish an effect of menstrual cycle upon the effect of cooling on strength. These preliminary data show pre-ovulation TA MVF is higher than post-ovulation (p=0.017). At skin temperatures <20oC MVF is lower than when >20oC (p=0.001). Handgrip strength at skin temperatures <25oC is lower than those >25oC, pre- and post-ovulation (p<0.001) irrespective of menstrual phase. There was no interaction between temperature and menstrual cycle for handgrip strength or TA MVF. The decline in handgrip strength with hand cooling occurred at a higher temperature (25oC) than for TA MVF (20oC). This is despite the fact that forearm muscles were not directly cooled, suggesting mechanisms other than local muscle cooling contribute to the decline in handgrip strength. TA MVF, but not handgrip, was lower post-ovulation suggesting an influence of female hormonal status may have been observed when the muscles were cooled directly. Further data is required to determine if there is an interaction between temperature and menstrual cycle phase on force.