Week 6 (1) - Protein Flashcards
Chronic effects of protein (Hartman et al 2007)
- 12 weeks resistance exercise training (5 sessions a week) with milk, soy or carbohydrate intake post-exercise (all energy and calorie matched)
- Milk enhanced body composition changes with resistance exercise
- Milk showed significantly greater lean mass gains than soy or CHO
- No significant differences in body mass
Chronic effects of protein (Josse et al 2010):
- Milk enhanced body composition changes with resistance exercise – greater gains in lean mass
- Greater loss in fat mass in milk group compared to control
Chronic effects of protein (Volek et al 2013):
- Whole body training for 9 months
- Whey protein, soy protein and carbohydrate supplements on training and non-training days
- Whey protein supplementation increased resistance-training included gains in fat-free (lean) mass compared to soy and carbohydrate
- Most of the gain that is experienced in lean mass happens at 3 months – with very little lose happening in the remaining 6 months.
Chronic effects of protein (Morton et al 2018) – systematic review:
- Protein supplementation produced small, but significant increases in:
- 1RM strength
- Fat-free mass (lean mass)
- Muscle size
- Found no effect on fat-free gain mass when protein intake was greater than 1.62 g/kg/day
Energy intake and hypertrophy/ strength
- An energy deficit above 500kcal a day is the point at which you start to see changes in lean mass occur (lean mass decreases)
Endurance exercise and protein balance (Wolfe et al 1982):
- BCAAs oxidised during exercise: Oxidation rate is dependant on CHO availability
- Generally contribute <5% energy
- On its own endurance exercise increase AA oxidation
- Rationales for increased protein requirements in endurance athletes: mitochondrial biogenesis
Resistance vs endurance training (Wilkinson et al 2008):
Untrained ppts:
* Myofibrillar: after endurance exercise there was no change in myofibrillar exercise. After resistance exercise there was a substantial increase
* Mitochondrial: endurance and resistance exercise caused an increase in mitochondrial PS
Trained ppts:
: resistance trained individuals had increased basal myofibrillar levels, which was further increased than that at rest. Endurance training caused an increase in mitochondrial proteins but resistance training caused no increases
* Trained muscle showed lowered PS increases after training
Protein intake and MPS (Breen et al 2011):
- 10 trained cyclist 90min cycling + hour recovery. Given 50 CHO or 50g CHO + 20g protein
- In the recovery period, protein intake increased MPS, but only in the myofibrillar fraction
- In the immediate 4hrs after exercise, providing protein helped with some of the structural proteins within the muscle but did not affect the endurance specific proteins
Alcohol and MPS (Parr et al 2014):
- Alcohol ingestion in large amounts reduces muscle protein synthesis
- 3 interventions: ALC-CHO, ALC-PRO, PRO
- Providing protein increased FSR the most
- Adding alcohol to the protein dampened the response
- Removing protein entirely (ALC-CHO) further dampened the response
Protein intake during exercise and performance (Breen et al 2010):
- 12 trained cyclists. 2hr steady state ride followed by ~1hr performance test
- During ride:
- 65g/h CHO
- 65g/h CHO + 19g/h protein
- Performance similar between trials
- No significant improvement or deficit when protein was added for the endurance exercise
Protein and muscle glycogen resynthesis:
- Adding protein to CHO you can amplify the glycogen resynthesis response
- Dose response relationship – ceiling of 1.2g/kg/hr
- 1.2g/kg/hr is v difficult to maintain
Protein and post-exercise rehydration (James et al 2011):
- Exercise-induced dehydration followed by rehydration with 2 drinks:
- CHO-only
- CHO-milk protein
- Addition of milk enhances rehydration
Endurance training adaption (Ferguson-Stegall et al 2011):
- 16 men and 16 women in 3 groups:
- CM: carbohydrate protein (milk based)
- CHO: carbohydrate
- PLA: placebo
- 5 session/ week for 4.5 weeks
- Drinks: immediately and 1hr post-exercise
- Carbohydrate protein intake enhances adaption to endurance training – greater gains in vo2 max were shown in the CM group
Protein requirements of athletes:
- Sedentary: 0.8g/kg
- Endurance athletes: 1.2-1.6g/kg
- Strength athletes: 1.2-1.7g/kg
- Increased requirement during energy restriction: 2g/kg (reduces lean tissue loss)
Athletic protein intakes: Old data from Dutch Athletes: (Van Erp-Baart 1989)
There is a strong correlation between energy intake and protein intake
- The greater the energy intake the greater the protein intake
To reduce protein deficiency, by default recommend an increased energy intake
Linear relationship: more energy = more protein.
