The aim of this article is to weigh up the pros and cons of training twice a day, as I’m sure you’ve all heard of rumours about reduced gains, or that you gain lean muscle faster. With lots of conflicting factors around this subject, hopefully you will be able to gain a clearer idea over which is the better choice for you personally…

So,

How much is too much??

Let me start off by saying that there is by no means a right and wrong answer to this, it simply depends on what your training goals are.

The reason some people (myself included) train twice a day is that training in a glycogen depleted state allows for greater mitochondrial growth as well as a greater capillary density, which are both vital for generating lean muscle mass.  Muscles have their own separate stores of glycogen, and the only way to reduce or deplete these – is to use those muscles. Hence, why training twice a day will mean your latter training session will occur with depleted muscle-glycogen stores.

To get complex; carbohydrates block the enzyme signal of AMPK, activated by AMP in the body, which allows AMPK to bind with the muscle fibre membrane – inducing hypertrophy in those cells.

Key study: Hansen (2005)

Seven untrained males took part in this 10 week training intervention, where they trained one leg in a ‘high glycogen state’ and the other in a ‘low glycogen state’

Training was very intense with the ‘low’ leg completing both an AM and PM session, while the ‘high’ leg trained only once: in the AM session.
Each session consisted of one hour of knee extensions at 75% of the individuals max power output

The ‘low’ leg was trained twice a day every other day, while the ‘high’ leg was trained everyday, with both legs having set rest days – which allowed for the same amount of total work performed by each leg to be the same.

After the 10 week training period, an isometric contraction (contracting against a fixed object so that the limb neither lengths or shortens) test was completed at 90% max power output.
Results found that peak force, time to exhaustion and total work done to be greater in the ‘low’ group, as well as having greater muscle glycogen stores, showing that training twice a day does have great benefits.

However, another study by Hickson (1980) had similar results with the key difference being in body mass.
Training twice a day resulted in a 1kg reduction in body mass, when compared with training once a day – which led to a 2kg increase in body mass.

Although the results are positive for the most part, if you train twice a day for a duration longer than 10 weeks (assuming you have appropriate rest periods) the gains found in strength and endurance capacity become reduced – due to over-training syndrome.

What does this mean for you?

• If your aims are maximum hypertrophy alone (muscle size) and to increase bulk, I would recommend that you stick to training once a day
• If your aims are to lose weight or gain lean muscle, I would advise taking part in a 6-8 week cycle where you try to complete two sessions a day, three times a week to help improve glycogen stores

Hope this was useful to you.

Cheers,

Andreas