Kreider R B, Miller G W, Williams M H, Somma C T, Nasser T A
Department of Health, Physical Education and Recreation, Human Performance Laboratory, Old Dominion University, Norfolk, VA 23529-0196.
Med Sci Sports Exerc. 1990 Apr;22(2):250-6.
Seven male competitive runners (VO2max 73.9 +/- 6.3 ml.kg-1.min-1) participated in a two-session, placebo, double-blind study to determine the effects of phosphate loading on oxygen uptake, ventilatory anaerobic threshold, and 5-mile run performance. Subjects ingested 1000 mg of tribasic sodium phosphate or a placebo four times daily for 6 d. A maximal running stress test or a 5-mile performance run was performed randomly on either the 3rd or the 6th d. Test sessions were separated by a 2-wk washout period and repeated with alternating phosphate and placebo regimens. Venous blood samples were collected prior to and following each max and run session. Results revealed that placebo resting serum phosphate levels were mildly elevated and that phosphate loading significantly increased resting and post-exercise serum phosphate values. Resting and post-exercise 2,3-diphosphoglycerate values were decreased while hemoglobin values were elevated with phosphate ingestion. Phosphate loading significantly increased maximal oxygen uptake from 4.77 +/- 0.29 to 5.18 +/- 0.25 l.min-1 and ventilatory anaerobic threshold from 3.74 +/- 0.28 to 4.18 +/- 0.14 l.min-1. Five-mile run times were nonsignificantly different between placebo and phosphate sessions. However, mean performance run oxygen uptake was significantly lower (3.87 +/- 0.3 to 3.80 +/- 0.3 l.min-1) with phosphate ingestion. Data demonstrate that maximal and run performance were influenced by elevations in serum phosphate eliciting an increased maximal oxygen uptake, ventilatory anaerobic threshold, and variable effects on 5-mile run performance. These adaptations occurred without observable increases in red cell 2,3-diphosphoglycerate.
七名男性竞技跑步运动员（最大摄氧量为73.9±6.3毫升·千克⁻¹·分钟⁻¹）参与了一项为期两阶段的安慰剂双盲研究，以确定磷酸盐负荷对摄氧量、通气无氧阈和5英里跑成绩的影响。受试者每天四次摄入1000毫克磷酸三钠或安慰剂，持续6天。在第3天或第6天随机进行一次最大跑步应激测试或一次5英里成绩跑测试。测试阶段之间有2周的洗脱期，并交替使用磷酸盐和安慰剂方案重复进行。在每次最大测试和跑步测试之前和之后采集静脉血样。结果显示，安慰剂组静息血清磷酸盐水平轻度升高，而磷酸盐负荷显著增加了静息和运动后血清磷酸盐值。摄入磷酸盐后，静息和运动后2,3-二磷酸甘油酸值降低，而血红蛋白值升高。磷酸盐负荷显著增加了最大摄氧量，从4.77±0.29升·分钟⁻¹增加到5.18±0.25升·分钟⁻¹，通气无氧阈从3.74±0.28升·分钟⁻¹增加到4.18±0.14升·分钟⁻¹。安慰剂组和磷酸盐组的5英里跑时间无显著差异。然而，摄入磷酸盐后，平均成绩跑摄氧量显著降低（从3.87±0.3降至3.80±0.3升·分钟⁻¹）。数据表明，血清磷酸盐升高影响了最大摄氧量和跑步成绩，导致最大摄氧量增加、通气无氧阈升高，并对5英里跑成绩产生不同影响。这些适应性变化并未伴随着红细胞2,3-二磷酸甘油酸的明显增加。
