International Fitness Scale-IFIS: Validity and association with health-related quality of life in pregnant women.

This study aimed (a) to examine the construct validity of the International Fitness Scale (IFIS) to discriminate between different objectively measured physical fitness levels in pregnant women and (b) to assess the extent to which IFIS is able to discriminate between pregnant women with different levels of health-related quality of life (HRQoL). A total of 159 pregnant women were involved in the GESTAtion and FITness project: 106 pregnant women (mean age 32.7, SD 4.4 years) were included. Self-reported physical fitness-that is, cardiorespiratory fitness, muscular strength, flexibility, and overall fitness-was assessed with the IFIS. Physical fitness was objectively measured using the Bruce test, the handgrip strength test and the back-scratch test. The HRQoL was assessed with the 36-item Short Form Health Survey (SF-36). Higher self-reported physical fitness measured with IFIS was associated with higher objectively measured physical fitness (P < .05). There was a linear association so that higher self-reported physical fitness (ie, IFIS; regardless of the fitness component) was related to greater General Health dimension scores (P < .05). Moreover, higher self-reported physical fitness (all components except muscular strength) was associated with better Physical Functioning, lower Bodily Pain and higher Vitality scores (ie, SF-36 components). This linear trend was not seen for objectively measured physical fitness. The results of this study suggest that IFIS might be a useful tool for identifying pregnant women with low or very low physical fitness and with low quality of life health-related. Further research should elucidate whether IFIS can identify women with pregnancy complications before it can be implemented in clinical practice.