et al. 1 Although they reported no significant advantage to Nordic walking (NW) over standard exercise, other individual studies have suggested otherwise. 2e4 Girold et al. and Spafford et al. concluded that NW significantly improved walking distance after four and 12 weeks, respectively. 3,4 This discordance may explain the significant quantitative (I 2 54e99%), and qualitative heterogeneity between studies, 1 arising from control differences (medical therapy, supervised treadmill walking) and age. 2 In addition, mean walking distance was estimated by multiplying the treadmill speed by walking time for some studies; 2 however, Table 1 highlights an alternative method, as multiplying summary effects do not give the summary quotient or product.