Have there been any studies or surveys which study association between strength, endurance, or other physical fitness measures in relation to vegan or vegetarian diets?
This 1999 study of students in the Flemish region of Belgium indicated that vegetarian youth had lower performance on strength tests but higher performance on endurance tests. The study had several limitations, including a small sample size.
Hebbelinck et al. (1999) conducted anthropometric analyses (stature, weight, skinfold thicknesses), puberty ratings (where appropriate), and physical fitness (handgrip strength, standing long jump, sit-ups in 30 s, and heart-rate recovery following a step test) of vegetarian children, adolescents and young adults in the Netherlands. Compared to reference values…
- Vegetarian adolescents were of significantly lower stature, weight and body mass index, but there were no differences in stature or weight for the other age groups.
- Vegetarian children were of equal fitness, but vegetarian adolescents scored lower on standing long jump and 30-s sit-ups.
- Heart rate of vegetarian adolescents and young adults recovered substantially faster following the step test.
Hebbelinck et al. concluded that vegetarian adolescents and young adults performed better at the cardiorespiratory test, but the vegetarian adolescents scored lower on the strength and explosive power tests. (Source: http://sportsci.org/jour/0201/cf-e.htm)
It all depends on the quality of food, daily excerise, and quality of sleep that enhances individual performance. My children are about 80 percent vegan. They seem healthier than when they ate a lot of animal products.
Personally, I am the healthiest I've been in my life since I've gone vegan.
Hopefully, there will be more studies soon.