Although gyms across the world are currently closed due to the Covid-19 pandemic, is it still possible to build muscle mass? Well, it really depends on a few factors about you as an individual and you're environment.
We need to consider three things. Your muscle adaptability. Your access to equipment. And your knowledge. It's your unique combination of these three factors that will determine whether you build additional muscle, maintain your current level of muscle or unfortunately, see a reduction in you're overall muscle mass.
This refers to the level of stimulus your muscles currently need. If you want to build muscle, over time there must be a gradual increase in volume. If you've been training for 5+ years, your muscles will require a tremendous amount of volume in order yo grow. Volume is comprised of three things, weight, reps and sets (sets x reps x weight = volume).
The more volume you require, the more adapted your muscles are. We can split this into three groups - high, medium and low.
High adaptability - Having usually trained for longer than 5 years, this group will have increased there lifts significantly overtime. The amount of weight they'll be lifting can usually only be facilitated by a gym. Weights will be lifted for a multitude of rep ranges spanning from 3-50 and the number of sets within each workout will be vast. Muscle needs a huge amount of stimulus to continue growing, leaving this group most susceptible to depletion of muscle.
Medium adaptability - Approximately 1-5 years of serious training will see you fall into the medium adaptability category. This group is limited by strength and therefore only requires a moderate amount of weight. They are still working on building a strong foundation for explosive power and rely heavily on different training methods, capitalising on high numbers of reps and sets. Given the right surroundings this group is most likely to maintain, but may either increase or decrease muscle depending on knowledge.
Low adaptability - This group commonly have under 1 year of training behind them. Minimal amount of weight and reps required in order to stimulate muscles. For this reason, sessions are shorter meaning less exercises and therefore less sets required. Overall volume of sessions is lower and muscles are constantly overwhelmed with the stimulus put on them. This group has a high probability of gaining muscle under the right circumstances..
Access to equipment
What's your home set up like? This (quite obviously) plays a huge role is your ability to stimulate muscles. Over the past few months I've seen some people invest thousands creating a home gyms which include power racks, barbells, plates, dumbbell sets, cable machines etc. Most who are passionate about building muscle will have tried to get there hands on at least some resistance bands and/or a pair of dumbbells/kettlebells/barbells. Others may be left simply with bodyweight exercises.
Those with a high muscle adaptability will need high numbers of weight and a more advanced set up to carry on building muscle. Those with medium adaptability will need some weights but, have the potential to build muscle by utilising sets and reps. Those with a low adaptability, given the right programming, have a great chance of building muscle with simple bodyweight exercises.
Quite simply, the more you know, the greater potential there is for muscle growth. A more advanced understanding of the physiology, biomechanics and training methods will likely lead to more outside the box thinking and greater creativity. The greater your muscle adaptability the more thinking will need to be applied.
My advice - Use this time to really educate yourself on the fundamentals of building muscle. Whether it's watching videos on new exercises, reading articles about training methods, buying books on how the body functions, use this time wisely. The great thing about our current situation is content has gone through the roof. There's no shortage of workouts videos or articles. Knowledge is power (literally and metaphorically).
Take care, stay safe.