It makes sense to me that for endurance sports like running and cycling, there are huge advantages to being leaner, because the leaner the athlete (as measured by body fat), the more economical their movement and the faster he/she can travel.

But leanness by itself does not seem a good predictor of athleticism (for endurance sports). Leanness is only a descriptor of physique and leanness does not equate fitness.

Instead, better predictors of performance seem to be things like power output, training volume, VO2 max, maximum speed and running economy.

My thinking, however, has changed after reading this article describing the findings of two surprising (at least to me) studies that body fat percentage was among the best predictors of race finish times, in both recreational runners and elite runners:

  • “The researchers found an 80 percent correlation between skinfold measurements and race times in the men and a 78 percent correspondence in the women. All of these runners were very lean and very light, but the leanest among them were the fastest.”
  • “At every level of the sport, leanness is as important as aerobic capacity, speed, and running economy. And even at the elite level, it seems, some runners could get faster by getting leaner.”

So, if 100 random people run a foot race, you have a good chance of predicting the outcome just by seeing who is lean and who is not.

View from gym



  • Breakfast: one cup of oats with strawberries
  • Lunch: veggie burrito
  • Dinner: mixed salad – brown rice, purple cabbage, carrot, corn and dressing (beans, capers, vinegar, maple syrup, lemon zest, lemon juice, black pepper, garlic, ginger).

Workout at gym:

  • 5 minute stationary bike
  • Bicep machine (33kg), tricep machine (25kg), dumbbell kickback (8kg), reverse curl (17.5kg)
  • Three sets of 40kg squats, 8 reps each set, followed immediately by 16 steps of walking lunges holding two 8kg dumbbells
    • The last bit was difficult
  • For running – resting today and tomorrow and a hard 10-14km effort on Saturday morning.