As mentioned in part 1 of why we periodise our group fitness program, unlike many group fitness gyms, we don't just pick a random session every day, or do a 'workout of the day' filled with cool-looking exercises for the 'sake of the burn'.
If you want a long-term plan to get sustainably fitter and stronger, then you need to periodise your training.
One unsexy truth about effective programs - they all include repetition!
"The time required to be an expert in any given area has been estimated at 10,000 hours, or approximately 10 years, of direct practice" (Ericsson et al, 1993).
If you want to get better at something, you need to practise it.
If you want to get better at juggling, you juggle.
The same applies in the gym. If you want to get better at a deadlift, then you deadlift.
Strength exercises are motor patterns which have a learning element to them, they are associated with the same neuroplastic changes in the central nervous system as specific 'skill' training (Leung et al, 2015).
This means that we need to practise finding the most efficient/optimal technique in order to execute a better lift. The more you practise them, the more efficient you become at firing neurons within the working muscles, enhancing your intramuscular coordination as well as your ability to generate force - aka getting stronger (Jensen et al, 2005).
If you change the novelty of the task too frequently (constantly doing new exercises), the rates of improvement may not be as high. Repetition and practise, paired with applying the principles of progressive overload are the most effective combination to improve your strength and fitness.
Once we've had a chance to practise movements, we test them! Every 12 weeks we test a variety of exercises (specific to our program) so that we are able to assess, rather than guess, our progress.
Doing something random every time and then testing an arbitrary group of exercises is not specific to what you've been doing, so you may not get a proper gauge as to how you've actually been progressing (if at all).
For example, if you want to include bench press/deadlift/squat etc as testing markers of strength, then they need to be included in your program consistently.
As Bruce Lee once said: "I do not fear the man who trains 10 000 different kicks once, I fear the man who trains 1 kick 10 000 times."
How can you expect to become a master at your craft if you train via novelty and not with purpose?