Hand forces exerted in 120 different combinations of foot positions, hand positions, and force directions were measured in a group of 15 male adults with acute low-back syndromes. The performances of these patients were contrasted with those of 29 healthy male adults who had been tested earlier. The major findings were: acute back syndrome patients, sometimes even including those with very severe pain, have considerable physical ability in many of the situations examined, often fully comparable to that of healthy subjects; generally, either patients were unable even to assume a given position, or else their performances were close to normal in all exercises in each position; the positions which a significant number of patients could not assume were those involving substantial trunk twisting, or combinations of bending and twisting.