Author and graduation date: Antonio M ONTIVEROS, November, 2000

Committee members: Peter Francis(Chair), Peter Francis, Jeanne Nichols, Karen May-Newman, Vert Mooney

Thesis title: The Effects of Isotonic Cervical Strengthening on Isometric Strength of the Lumbar Musculature

This study investigated the effects of isotonic cervical strengthening on isometric strength of the lumbar musculature using the MedX^TM Lumbar and Cervical Extension machines. Thirty-two healthy male and female subjects participated in the study. Sixteen subjects trained twice per week for six weeks and 16 subjects acted as controls. Training consisted of 8-12 repetitions of full range of motion variable resistance cervical extension exercise to volitional fatigue. Prior to initiating the training and upon completion of the six-week training program, all subjects completed a maximum isometric strength test for the cervical and lumbar musculature. The cervical isometric strength test was evaluated at eight standardized angles through a 126^o cervical range of motion (0^o, 18^o, 36^o, 54^o, 72^o, 90^o, 108^o, 126^o) on the MedX^TM Cervical Extension machine. The lumbar isometric strength test was evaluated at seven standardized angles through a 72^o lumbar range of motion (0^o, 12^o, 24^o, 36^o, 48^o, 60^o, 72^o) on the MedX^TM Lumbar Extension machine. The values obtained at each of the discrete positions were summed to produce a value for the aggregate cervical torque and a value for the aggregate lumbar torque. There was a significant difference between groups for percent change for cervical extension aggregate torque (t₃₀ = -4.653; p = .001). The training group improved 40.7% as compared to the control group at 18.8%. There was also a significant difference between groups for percent change for lumbar extension aggregate torque (t₃₀ = -4.487; p = .001). The training group improved 17.9% as compared to the control group at -1.4%. These findings demonstrate that when the cervical musculature is trained isotonicaly, with the lumbar musculature isolated, there is a significant amount of lumbar strength improvement due to substitution.

Click here to return to the Completed Master Degree Theses in Biomechanics Table of Contents