Is there a real difference between morning workouts and later ones when we talk about muscle hypertrophy?
This question was tried to answer by a group of researchers from Finland and Slovakia in their fundamental paper - Morphological, molecular and hormonal adaptations to early morning versus afternoon resistance training.
It has been clearly established that maximal force and power is lower in the morning compared to noon or afternoon hours. This morning neuromuscular deficit can be diminished by regularly training in the morning hours.
However, there is limited and contradictory information upon hypertrophic adaptations to time-of-day-specific resistance training. Moreover, no cellular or molecular mechanisms related to muscle hypertrophy adaptation have been studied with this respect.
Therefore, the present study examined the effects of the time-of-day-specific resistance training on muscle hypertrophy, phosphorylation of selected proteins, hormonal concentrations and neuromuscular performance.
The study involved 25 young people (from 20 to 30 years) previously untrained. Participants were divided between groups engaged in the morning hours (7-8.00) and the daytime (16-17:00). The control group consisted of 7 people.
Both the morning and afternoon group underwent hypertrophy-type of resistance training with 22 training sessions over an 11-week period performed between 07:30-08:30 hours and 16:00-17:00, respectively.
To maximise the hypertrophy, subjects took 25 grams of protein (BIO5 Whey Better) with 0.4 litres of water immediately after training. The control group also took protein, but at lunchtime.
- Voluntary muscle strength increased significantly in both the morning and afternoon training group by 16.9% and 15.2 %, respectively. Also, muscle hypertrophy occurred by 8.8% and 11.9% and at muscle fibre CSA level by 21% and 18% in the morning and afternoon group, respectively.
- It was shown that the intake of 20-25 grams of protein immediately after training promotes the synthesis of protein and subsequent hypertrophy (Hulmi et al. 2009, Lane et al. 2017, Churchward-Venne et al., 2012).
- Resting testosterone was not statistically different among groups at any time point. Resting cortisol declined significantly from pre- to post-training in all three groups.
Similar levels of muscle strength and hypertrophy could be achieved regardless of time of the day in previously untrained males. However, at the level of skeletal muscle signalling, the extent of adaptation in some parameters may be the time of day dependent.
The obtained data allow concluding that in 11 weeks of training, people who do not have the experience of strength training can achieve the same level of strength and hypertrophy, regardless of the time at which the strength training for hypertrophy was conducted.