From the Center for Exercise Science, Departments of Medicine, and Exercise Sport Sciences, University of Florida, Gainesville, Florida.

7. Abstract
Quantification of cervical extension (CERV EXT) strength is complicated by the inability to stabilize the torso and isolate the CERV EXT muscles. A newly developed machine designed to stabilize the torso and isolate the CERV EXT muscles was used to evaluate the effect of frequency and volume of resistance training on CERV EXT strength. Fifty men (age, 26 ± 9 years; height, 174 ± 16cm; weight, 74 ± 9kg) and 28 women (age, 30 ± 9 years; height, 152 ± 32cm; weight, 62 ± 7kg) volunteered to participate. Subjects were randomly stratified to one of four training groups or a controlled group (CONT, n = 19) that did not train. Each training group exercised for 12 weeks as follows; once per week using one set of dynamic exercise (DYN 1X/wk, n = 14), once per week using one set of dynamic exercise and one set of maximal isometric (IM) exercise at eight angles through a 126° range of cervical extension (DYN-IM 1X/wk, n = 16), DYN 2X/wk (n = 19), or DYN-IM 2X/wk (n = 10). Maximal IM torque was measured at eight angles initially and after 12 weeks of training. All training groups improved CERV EXT strength (r £ 0.05) at all angles tested compared to the CONT except for DYN once per week at 0° of CERV flexion. A greater increase in strength was found when the groups trained two times per week were compared to those that trained once per week. The results indicate that only a single set of CERV EXT exercise is required to attain a full range of motion increase in strength as long as the training frequency is at least two times per week.