(We assume you have a basic understanding of strength training. This includes the concepts of sets of exercises, and repetitions of an exercise making up a set. You'll have used strength gym equipment, if only briefly, and know that progressively overloading a muscle brings microscopic injury, which in turn causes new growth that increases strength. (Hypertrophy) You'll also know that strength training has many short and long term health and life-quality benefits, and that it both improves strength and function, and can improve heart-health and many other health aspects)
There are many options, styles, program choices and designs for strength training. Rather than let it become bewildering, the best thing is to get started, and get a feel for the doing of it. Going with a basic program with simple steps and structure can get you into a pleasure zone and sense of achievement early, without limiting future options. Reading, learning and creating new plans as you go can very enjoyable. The important thing to remember is to include compound exercises as the basis or your plan or program. Compound exercises are the multi-joint major presses, pulls, lifts and squats that form the basis of a full-body training plan, and match the major functional movements of the human physique.
Choices of approach. There are two basic structures you can choose from to start trainng. The first is a simple, set-based plan. You do a set of say, 6 to 16 reps on one exercise. You rest. You do another set. Rest; then another; etc..
The other structure is a circuit. Here you work at a pace you choose - and do x reps of one exercise, take a 60 second break, then do (say) a set of another set, rest, and so on. At the end of y sets, you call it a circuit. Take a 60 second break, and you can do another circuit...and another, etc.
Either style can take you towards useful goals, such as strength, fat loss or even cardio gain. Circuits introduce a pace and a keep-moving sense that many people find useful; it discourages distraction which happens so easily. Or go with sets for a while, and change to circuits if you want; it's easy enough.
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