There is provided a method of indirectly estimating muscle strength ratio, comprising: receiving images and associated body part locations of a target individual, wherein the images depict the target individual performing a first and a second defined movement, identifying first image(s) depicting the first defined movement, and obtaining an associated first set of body part locations, identifying second image(s) depicting the second defined movement, and obtaining an associated second set of body part locations, computing a first image-metric according to the first set of body part locations, computing a second image-metric according to the second set of body part locations, computing an image-parameter according to the first and second image-metrics, and converting the image-parameter to an estimate of a measured-parameter indicative of strength measurement ratio of the target muscle(s) obtained by a dynamometer, according to correlation between image-parameters and measured-parameters obtained based on the dynamometer performing empirical measurements.