Not sure what you're going to do in the gym today? That's ok if you've got no specific goals. If however, you are trying to achieve something specific, you will need a plan. We know plans as 'training programmes' in the context of the gym but so many people fail to plan, and so plan to fail...
Random exercise has gained a lot of attention in the last decade as one particular 'system' burst onto the fitness scene - Crossfit. The whole premise of Crossfit is to prepare people for the random. To use random methods to adapt to random stimulus. There is only one small problem with this approach.
Before I continue let me explain, I am a weightlifting coach AT A CROSSFIT GYM. I am not a certified Crossfit coach nor do I claim to be a 'crossfitter'. I barely claim to be a weightlifter if we're honest but that is my current preferred training modality...
I occasionally do some crossfit workouts and some 'crossfit style' workouts of my own design too. They're great for general conditioning and work capacity.
Back to the problems with randomness...
Your body likes structure, it likes small progressive overload and importantly your brain needs repetition of the same or similar things to learn and get better at those things. Things like movement. When a programme is TOO RANDOM you struggle to learn and apply correct motor patterns - coordinated sequences of muscle contraction resulting in a movement outcome. Complex movements require well rehearsed motor patterns that are both limited in their exposure and progressive in nature.
Overexposure to single movements - here I'm talking about fatigue in a single setting. Think about trying to learn to ride a bike or learning to swim. If, with either of these SKILLS, you just kept doing them badly until too tired to do anymore, you likely wouldn't be efficient at getting better. Sure you'd end up fitter, maybe even leaner if you also watch what you ate. More likely is you'd get hurt or drown in the process.
Planning how much of a certain activity and how often is key.
Progressively more complex - day one of swimming you may learn to kick whilst holding onto the side of the pool. Day 5 you may hold a float and kick. You may not learn to move your arms for front crawl until much later on. We know how humans learn, we've studied it since the before the ancient Greeks. Graded exposure to more complex movements allows us to add up parts of a movement puzzle. Snatching and muscle ups also require a certain level of strength that limits how quickly they can be mastered.
Gradual is important.
Strength training is a gradual process of your central nervous system adapting to more effectively recruit your existing muscle mass and to lay down some new muscle (sometimes). This requires slow and steady increases in loading. We call it progressive overload. If we lift totally at random, we stop and start this progress always changing the stimulus on the body and we blunt the strength training effect.
Even the best athletes in the world who compete in random sports (things like rugby even where no two games are exactly the same) usually follow programmes that apply these principles. Practice makes perfect, or rather perfect practice makes perfect. Learn something, get ok at it, add some randomness later.
There is a time and place for most things. Randomness is a great testing tool, or a good tool for developing fitness in a general sense. The tools used within that random structure MUST be things that you HAVE ALREADY MASTERED for them to be safe and effective as conditioning exercises.
Structure and graded progressions for learning. Random for testing and conditioning.
A great example of using structured progressive training is my client Mel who is now busting out reps of chin ups when previously they had eluded her, despite being fairly strong in a general sense. Specific programming has lead to sets of 3-4 reps becoming routine. Check her chin ups out on my Insta link!