The best way to go about this is to look at the 2 exercises where the belt is used most commonly, the squat and deadlift. From a therapist perspective, I don't understand why therapist are afraid to use these exercises, they are the most functional and effective exercises you can do. You get positive results relatively quickly however they can be hard exercises to learn the proper technique if your not familiar with them.
For the squat, when you unrack the bar you typically draw in the abdomen to increase your intra abdominal pressure to assist stabilising your back and give you a solid trunk/core to stabilise the weight, you maintain this until you get your foot position. Get your breath, draw in your abdomen again and start to descend starting from your hips and not your knees (depending on the squat). You maintain this fixed abdominal position throughout the entire lift and breath out in the last stage of the concentric part of the movement where you partially relax the core (Core meaning: abs, trans abs, internal and external obliques.). You need this stability to enable you to get sufficient drive from your legs (This goes back to the kinetic chain theory which is is either accepted of not by therapist and physical trainers.). In the squat itself the majority of the drive comes from the calves, quads, hamstrings, glutes and lumbar extensors but don't forget your antagonists in lifting and training so your abdominal area is just as important.
The ability for your core to work effectively depends on 2 parts, firstly and probably most obvious, your personal exercise experience (years spent training the right way). Secondarily is your foot position and how wide apart your legs are. The wider your feet are apart the more upright your body is meaning you will require less core stability (Larger base of support) on the lift as there's minimal shift in your centre of gravity. This is more apparent with heavy powerlifters that squat 400kg + and use a lot of strength and power and the olympic weightlifters who typically have a narrow stance but use more momentum and power.
Utilising your core is quite difficult and very draining (on your muscular and central nervous system) throughout a full body exercise like the squat, so experience is the key. In theory, for proper technique it will only take about 6 weeks (so not long to get your core working efficiently), then you only need to build up your resistance.
So when using a belt for any exercise you usually have the belt around you lower lumbar and abdomen. With a belt in place push your abdomen into the belt (and not draw in) to increase intra-abdominal pressure therefore supporting your back. The difference with a belt is that you can vary your intra-abdominal pressure throughout a lift. With regards to the squat when your at the bottom of the lift (In the most flexed position) you can push into the belt more which will help you drive out of the bottom of the lift. However using a belt doesn't mean you don't use your core, you just use it in a different way. A tip for therapist if your client has recti diastasis I would advise against a belt.
A belt will only help depending on what type of belt you use. A thick leather belt will give you more support throughout a lift in relation neoprene belt as neoprene belts help more with utilising your core by drawing your abdomen in because if you push into it it won't give you the support you require. With belts there are a variety of belts that you can use and if you want to know the differences then I would suggest to look at a previous blog I have done.
For the deadlift the principles are the same however I find the use of a belt helpful on the initial part of the lift as I drive my abdomen into the belt at the same time I drop my hips, this helps me get the weight of the floor quicker. With the deadlift I find I use my core more on the eccentric part of the lift and push into the belt for concentric part of the lift. Ideally you keep the same technique on eccentric as the concentric but I use this to ensure my core is getting trained because I don't get time to train specifically my core, so I introduce in certain exercises.
With regards to using belts on a deadlift there is no rule of which one is the best it's what works for the individual, but due to the flexion some prefer a tapered belt so it doesn't inhibit the end range flexion. I find this is dependent on the type of deadlifter you are (Back or leg). I'll refer you to my blog on different styles of belt and their use.
For a the majority of the clients I see I suggest start with what you finish with. For example, if for your max lift you use a belt make sure you start wearing a belt from your first working set after your warm up. This is mostly to maintain consistency throughout your work out and reducing risk of injury (You don't change your exercise form as you get heavier so why should you change how you support your body.) Another time which is appropriate for using a belt towards the end of your work out would be if your fatiguing and your technique is suffering and only then would i suggest a neoprene belt.
The only time I would suggest against wearing a belt is if your sport doesn't allow it and i would only use a belt for these individuals if you were looking at training a particular aspect near to their 1RM (Eg.heavy squat, snatch, clean and jerk, etc.).
- Try a belt before you buy one
- Dont go with the fashion as this could be an expensive waste of your money and time.
- For heavy strength lifts i would suggest a leather belt. Start with a small thickness and build up.
- Single or double prong is more your preference (Double prong is suppose to be a firmer fit but tbh the difference is minimal if any)
- I use tapered belts for people that require deep flexion (weightlifters and deadlift) to prevent restricted range. To be frank if you have a belly i wouldn't use a tapered as it tends to cause discomfort.
- Go with a belt that ultimately suits you.
Hope that helps