BY

CLANCE LAYLOR

Resistance exercise is fundamentally anabolic, however in the absence of nutrient provision, net protein balance (muscle protein synthesis – muscle protein breakdown) remains negative (Phillips 2004). With the habitual performance of resistance type exercise, fasted state (i.e. between the post absorptive state and the consumption of a mixed meal) protein losses are reduced and fed state protein gains are enhanced, such that over time, appreciable gains in muscle mass become evident (Phillips 2004). There remain fundamental differences between the phenotypic changes associated with resistance exercise and endurance exercise. Resistance exercise is generally associated with increases in muscle mass (hypertrophy), and muscle strength, while endurance exercise is associated with changes in muscle oxidative capacity, without significant increases in skeletal muscle mass. However, the evidence suggests that these different modes of exercise are incompatible (Hickson 1980). For example, the performance of concurrent resistance and endurance exercise programs has been shown to result in a reduced adaptation compared to the performance of either exercise mode alone (Hickson 1980). From a molecular standpoint, it is becoming clear that resistance exercise and endurance exercise are associated with the activation of different signaling cascades within the cell, and that these signaling pathways may be incompatible (see Barr 2006). However, from an applied perspective it is clear that many sports exist along a continuum, requiring on the one hand, performance of short duration, high-intensity muscle contractions (characteristic of resistive type exercise) as well as the performance of continuous, long(er) duration, low(er) intensity muscle contractions (characteristic of endurance type exercise). 

                                                At Laylor Performance, our goal is to help athletes succeed in their respective sports. Hockey player Luke Tucciarone, a defensemen started training at Laylor June 1, 2009. He entered our facility at a bodyweight of 237 lbs, at approximately 26% bodyfat. Following 11 weeks of training, centered around the performance of resistance exercise, Luke’s bodyweight was reduced to 210 lbs and his bodyfat was reduced to 16%.  Despite this dramatic loss in bodyweight, Luke’s lean body mass (i.e. skeletal muscle tissue (LBM)) was essentially unchanged (176 lbs. pre-training, 177 lbs. post-training). Thus virtually all of the weight loss was in the form of bodyfat, while his muscle tissue was completely preserved during this time. Given the correlation between muscle cross-sectional area and strength, preserving LBM would appear to be of the utmost importance to an athlete during a weight-loss program so as to maintain strength levels.

                        What is clear is that the performance of resistance based exercise in conjunction with high(er) protein consumption during an energy deficit can help preserve LBM, and increase fat loss.

REFERENCES                  

Barr K.  Training for endurance and strength: lessons from cell signaling. Med Sci Sports Exerc 38 (11): 1939-1944, 2006.

Hickson, R.C. 1980. Interference of strength development by simultaneously training for strength and endurance. Eur. J. Appl. Physiol. Occup. Physiol. 45: 255–263.

Phillips SM.  Protein requirements and supplementation in strength sports. Nutrition 20: 689-695, 2004.