Effect of calcium supplementation on cycling performance in 10 mile time trials

The objective of the current research was to investigate the effect of calcium supplementation on cycling performance. Ten male well‐trained cyclists (mean ± SD; age 35.8 ± 11.3 yrs, stature 176 ± 7.1 cm, body mass 73.8 ± 9.3 kg, V̇ O 2peak 4.59 ± 0.8 l/min, W peak 350 ± 42 W) were recruited. Participants were tested using a randomised, single blind, test‐retest intervention trial design. Each participant was given 1000 mg/d of elemental calcium (citrate) in tablet form for 4 weeks. They undertook a 10 mile bicycle ergometer time trial test at baseline (10TTB) and end of the intervention period (10TTC). A stationary electromagnetically braked ergometer (SRM ergometer; Schoberer Rad Messtechnik, Jülich, Germany) was used. Gas exchange was measured continuously using an online breath‐by‐breath Spirometer (Metalyzer II; Cortex, Leipzig, Germany). There was a drop in time‐to‐finish (−0.20 ± 0.11 mins; P = 0.17, d = −0.18) and mean power output increased (7.22 ± 0.65 W; P = 0.02, d = 0.21) in 10TTC compared to 10TTB. Both mean gross efficiency (1.19 ± 0.40%; P = 0.001, d = 1.09) and mean economy (4.15 ± 1.41 W/l; P = 0.001, d = 0.82) improved significantly during the 10TTC compared to 10TTB. Increased dietary calcium may have improved performance via changes in intracellular calcium [Ca 2+ ] i levels. Efficiency may have improved due to a combination of better utilisation of metabolic substrates and attenuated skeletal muscle fatigue.