The effect of protein and carbohydrate supplementation on strength training outcome of rehabilitation in ACL patients

Abstract

Patients with anterior cruciate ligament (ACL) injury experience atrophy and weakening of the extensor as well as the hamstrings muscles at the injured leg. Especially, the weakness of the quadriceps muscle has been ascribed to hamper daily physical tasks. The purpose of the present study was therefore to investigate if nutrient supplementation during 12 weeks of conservative rehabilitation strength training could enhance hypertrophy and strength of the quadriceps muscle in ACL-injured patients. Twenty-six ACL-injured men and women were included and randomly distributed into three supplementation groups: Protein þ Carbohydrate (PC), Isocaloric-Carbohydrate (IC), or Placebo (PL), ingesting the supplementation immediately after each of 36 training sessions. Determined from images of thigh cross-sections (magnetic resonance imaging) the hypertrophy of the quadriceps muscle differed significantly between groups at the distal part, with the PC group demonstrating the largest hypertrophy. Peak torque of the quadriceps muscle at constant velocity 608 Á s À1 was significantly elevated in the PC group only, and the time to reach peak torque tended to decrease as well only in the PC group. The results from this study demonstrate that restoration of the distal vasti muscle mass and knee extension muscle strength with resistance training is promoted further by protein-containing nutrient supplementation immediately after single exercise sessions. Thus, exercise-related protein supplementation may seem important for surgery-related rehabilitation of skeletal muscle. ß

Consumption of fat-free fluid milk after resistance exercise promotes greater lean mass accretion than does consumption of soy or carbohydrate in young, novice, male weightlifters

“…Esmarck et al (33) reported that delaying the postexercise delivery of a protein-containing supplement to elderly men by 2 h prevented exercise-induced hypertrophy and slowed strength gains. In addition, strength and muscle mass gain in patients who had just undergone knee surgery were promoted to a greater degree by protein and carbohydrate consumption than simply carbohydrate or a placebo (34). Hence, the data presented here, combined with previous data from chronic studies manipulating postexercise protein consumption (31,33,34), support the general thesis that immediate consumption of protein, particularly milk protein, after resistance exercise serves to maximize exercise-induced increases in muscle mass.…”

Contraction intensity and feeding affect collagen and myofibrillar protein synthesis rates differently in human skeletal muscle

“…Also following exercise, nutrients and especially amino acids enhance muscle protein turnover markedly (93,105), and, when applied in long-term training studies, the nutritional supplementation and timing are important determinants for the accretion of muscle mass (48,54,102). In the present setup, LL contractions did not improve the myofibrillar FSR above the nutrient-induced level achieved at rest.…”

“…As seen sometimes during fasting conditions and reported once except from this study when fed continuously (23) and also following a single bolus intake dependent on its timing (38,96), the postexercise increase in muscle protein synthesis can be delayed. Thus controversy exists as to why an immediate intake of protein and nutrient supplementation is of major importance for the overall protein accretion in response to training (1,33,54). It may be speculated that an early intake initiates processes that, despite their immediate inhibition, extend the period where the exercise is anabolic.…”

Whey and casein labeled withl-[1-13C]leucine and muscle protein synthesis: effect of resistance exercise and protein ingestion

“…Resistance exercise, either alone (5,13,47) or in combination with AAs or whole proteins (6,11,44), is able to increase muscle protein synthesis (MPS), and as a consequence of repeated training sessions muscle mass and strength will increase (1,29,30). Furthermore, it has been shown that 20 g of protein seems to be sufficient for maximal stimulation of MPS (15,44).…”