Isometric exercise

Population

Mathematics

Biology

Statistics

Physical therapy

Ecology

Flexibility (engineering)

Trunk

Medicine

Environmental health

Physical medicine and rehabilitation

Journal of Rehabilitation Medicine

The strength and endurance of the trunk muscles was studied in relation to the extent of earlier low-back trouble (LBT) in a homogeneous, and occupationally active group. Twenty-four female and 53 male postmen with an occupational seniority of more than 2 years took part in the investigation. The cumulative lifetime prevalence, the one-year and the point prevalence of LBT were 67%, 62%, and 4% in females and 55%, 52%, and 0% in males. The rates are higher than in a representative Danish population 40 years old. Anthropometrical measurements and isometric strength (MVC) in trunk flexors and extensors were recorded. The flexibility of the spine, hip and knee joints, the fingertip-floor distance, and the restricted extension of the knee were evaluated. The isometric endurance in the trunk extensors was measured by two methods: 1) prone with the unsupported trunk in a horizontal position and the legs and hips fixated to a couch; and 2) standing, at 60% MVC. The participants were divided into three groups according to the extent of previous LBT, Group I: LBT to a degree that made work impossible, Group II: LBT experienced but not to such a degree that work was hindered, and Group III: LBT never experienced. The main findings were that the isometric endurance time of the trunk extensors was shorter in group I than in II and III, while the trunk muscle strength, anthropometrical measures and joint flexibility were independent of the persons' earlier low-back episodes. Differences in the distribution of ST and FT muscle fibres are suggested as an explanation of the endurance difference.

Trunk Strength, Back Muscle Endurance and Low-Back Trouble