What did Katzmarzyk et al. (2002) find?

Key numbers

Who was studied and what was measured

The study set out to measure how musculoskeletal fitness relates to death from any cause in the Canadian population. It drew on 8116 people from the 1981 Canada Fitness Survey (3933 men and 4183 women) aged 20 to 69 at the start. The fitness measures were sit-ups, push-ups, grip strength and sit-and-reach trunk flexibility, and the authors described sit-ups as a measure of abdominal muscular endurance.

How follow-up and analysis were done

Deaths were tracked for 13 years after the survey: 238 deaths over 101,685 person-years.

Each fitness measure was split into quarters within each age and sex group, and the top quarter was the comparison group. All models adjusted for age, smoking, body mass and estimated VO2max (aerobic fitness).

What the study found

Sit-ups stood out. Compared with the top quarter, men in the lowest quarter had a relative risk of death of 2.72 (95% CI 1.56 to 4.64) and women 2.26 (95% CI 1.15 to 4.43). The authors concluded that some parts of musculoskeletal fitness, particularly sit-ups, were predictive of mortality in this population.

There was no pattern of higher risk across quarters of push-ups or of trunk flexibility. Grip strength was not linked to mortality in women. In men, the lowest quarter of grip had a relative risk of 1.49 (95% CI 0.86 to 2.59), which was not statistically significant.

What this does not show

These are associations, not proof that doing more sit-ups lengthens life. A null result for push-ups or flexibility is not proof that those capacities have no possible benefit either. None of these tests is a Systematic test: the study's push-ups were not the Systematic tempo push-up and sit-and-reach is not the Systematic toe touch, so the study does not validate any Systematic score.

The evidence

Each cited source is labeled according to how it supports the particular claim on this page. Direct test evidence, underlying-capacity findings and population reference values are distinguished from Systematic-defined protocols and standards. Historical development notes are retained internally rather than presented as public evidence. A study of an underlying capacity is never presented as validation of the Systematic test itself.

• Underlying-capacity evidence New source

  Katzmarzyk et al. (2002). Musculoskeletal fitness and risk of mortality. Medicine and science in sports and exercise.

  What it found. In 8116 Canadians aged 20 to 69 followed for 13 years (238 deaths), the lowest quarter of sit-ups was linked to higher mortality than the highest (relative risk 2.72 in men, 2.26 in women).

  What it does not show. Push-ups and trunk flexibility showed no pattern and grip strength showed no significant link. It does not show cause, and it did not test any Systematic test.

  PubMed 11984288