How SportLegs Works
“My University of Washington Sports Physiology professors say the idea behind SportLegs is ingenious, and we can’t understand why someone didn’t try this sooner.” -2004 email from triathlete Cameron Chesnut, Post Falls, Idaho
SportLegs jump-starts your muscles’ natural chemistry to make less lactic acid in the first place. It replicates the signal muscles obey to curb the excess lactate production that forms lactic acid.
Since the 1970s, modern atomic research tools have let scientists see how lactate, an organic metabolite found throughout the body, functions as “energy currency” to optimize fuel distribution throughout our complex network of muscles. Radioactive isotope tracers let scientists watch how muscles produce, consume and exchange lactate to power exercise. Lactate’s primary benefit is its speed, facilitating energy exchange directly between working muscles without circulatory plumbing, distributing muscle energy through tissue and even cell membranes without delay. Further research showed lactate’s magic is effective only within a narrow range of pH; if it becomes acidic, its instantaneous trans-membrane perfusion speed slows drastically. When this “Lactic Acid” occurs, athletic performance decreases, with attendant muscle “burn” and post-exercise soreness.
Continuing research suggested lactate becomes acidic as it pools in muscles, after muscles produce more than they can promptly consume, as typically occurs early in exercise. Studies since 1975 have shown muscles stop producing excess lactate in response to rising lactate concentration in the bloodstream. We theorized lactate supplementation before exercise could replicate this signal in time to prevent the oversupply situation in the first place. Our experiments beginning in 1989 showed pre-exercise supplementation was indeed effective, noticeably inhibiting formation of lactic acid, and preserving ideal pH environment to optimize the Lactate System’s energy contribution.
Brooks, George A. (1986) The lactate shuttle during exercise and recovery. Med Sci Sports Exerc 18:361-368
Brooks, G. A., T. D. Fahey, T. P. White, K. M. Baldwin. (2000) Exercise Physiology. Human Bioenergetics and its Applications. 3rd edn. pp 804-805. Mayfield Publishing Company.
Roth, D. A. (1991) The sarcolemmal lactate transporter: transmembrane determinants of lactate flux. Med Sci Sports Exerc 23:925-934
Donovan, Casey M., and George A. Brooks (1983) Endurance training affects lactate clearance, not lactate production. Am. J. Physiol. 244 (Endocrinol. Metab. 7): E83-E92
Wahren, J., P. Felig, G. Ahlborg and L. Jorfeldt. (1971) Glucose metabolism during leg exercise in man. J Clin Invest 50:2715-27258)
Ahlborg, G. (1985) Mechanism of glycogenolysis in nonexercising human muscle during and after exercise. Am J Physiol. 248(5 Pt 1):E540-5
Richter, E. A., B. Kiens, B. Saltin, N. J. Christensen and G. Savard. (1988) Skeletal muscle glucose uptake during dynamic exercise in humans: role of muscle mass. Am J Physiol 254:E555-E561
Brooks, G. A., G. E. Butterfield, R.R. Wolfe, et al. (1991) Increased reliance on lactate during exercise after acclimatization to 4,300m. J. Appl. Physiol. 71:333-341
Brooks, G. A., E. E. Wolfel, G. E. Butterfield, et al. (1998) Poor relationship between arterial lactate and leg net release during steady-state exercise at 4,300 m altitude. J. Appl. Physiol. 275:R1192-R1201
Freyschuss, U. and T. Strandell (1967) Limb circulation during arm and leg exercise in supine position. J Appl Physiol, 23:163-170
Ahlborg, G., L. Hagenfeldt and J. Wahren (1975) Substrate utilization by the inactive leg during one-leg or arm exercise. J Appl Physiol, 39:718-723
Ahlborg, G., L. Hagenfeldt and J. Wahren (1976) Influence of lactate infusion on glucose and FFA metabolism in man. Scan J Clin Lab Invest, 36:193-201
Poortmans, J. R., J. D.-V. Bossche and R. Leclercq (1978) Lactate uptake by inactive forearm during progressive leg exercise. J Appl Physiol, 45:835-839
Stamford, B. A., R. J. Moffatt, A. Weltman, C. Maldonado and M. Curtis (1978) Blood lactate disappearance after supramaximal one-legged exercise. J Appl Physiol 45:244-248
Gladden, L. B. and J. W. Yates (1983) Lactic acid infusion in dogs: effects of varying infusate pH. J. Appl. Physiol. 54:1254-1260
Dodd, S., S. K. Powers, T. Callender and E. Brooks (1984) Blood lactate disappearance at various intensities of recovery exercise. J Appl Physiol 57:1462-1465
Stanley, W. C., E. W. Gertz, J. A. Wisneski, R.A. Neese, D. L. Morris and G. A. Brooks (1986) Lactate extraction during net lactate release by the exercising legs of man. J. Appl. Physiol. 60:1116-1120
Mazzeo, R.S., G. A. Brooks, D. A. Schoeller and T. F. Budinger (1986) Disposal of blood [1-13C] lactate in humans during rest and exercise. J Appl Physiol, 60:232-241
Gladden, L. B. (1989) Lactate uptake by skeletal muscle. Exerc. Sports Sci. Rev. 17:115-155
Gladden, L. B., R. E. Crawford and M. J. Webster. (1994) Effect of lactate concentration and metabolic rate on net lactate uptake by canine skeletal muscle. Am. J. Physiol. 266:R1095-R1101
Sanders, Robert. Rehabilitating lactate: from poison to cure. UC Berkeley: Berkeley News May 23, 2018