A bilateral exercise movement is when both limbs are used in unison to contract the muscles, which creates force, and subsequently moves a given load as in the case of a back squat, deadlift, or barbell bench press. In contrast, a unilateral exercise movement is when each limb works independently of the other to create the desired movement, such as in the case of a lunge, box step-up, split squat, or DB floor press.

Now, when it comes to this debate, I do not think there is a right or wrong answer and ultimately, I think both types of exercises provide a host of benefits, can be used in a variety of ways and both should be included in any program, although when they are programmed will be influenced by the goals of the individual or program and the presentation on any potential muscular imbalances.

However, firstly, let us consider the evidence that unilateral exercises are not as effective at increasing muscle activation or force production when compared to bilateral movements. Consequently, it is unlikely they (unilateral exercises) would be able to increase maximal muscular strength or power to the same extent as bilateral movements. Subsequently, if these variables were important in an individual’s overall plan or goals, then the programming of bilateral exercises would need to be a priority.

Again, though that is not to say unilateral exercises should be avoided and these exercises can be used for strength development in all populations. They also do not overload the body to the same extent as bilateral exercises and might be programmed to add variation and create balance in the volume of an overall exercise program, whilst also managing intensity.

It is also important to realise that most people are not perfectly symmetrical; therefore, implementing unilateral training into a program can address muscular asymmetry issues, as by training each limb separately, you can better ensure that they are both getting worked equally and one side is not overcompensating for the other. The more symmetrical our muscles are, the less imbalances we have, which improves our ability to evenly distribute workload between limbs when exercising, and his not only reduces our risk of injury but can also increase our overall strength as well (unlikely to the same extent as bilateral exercises though).

Take a back squat for example. Most people are not going to distribute the workload equally between limbs and will have their dominant side handling more of the load. By incorporating exercises like weighted lunges, box steps-ups and single leg RDLs into a program, you will likely see an improvement in bilateral movement patterns.

So, I think to summarise, I would recommend prescribing both unilateral and bilateral training to any exercise program to ensure a well-rounded training program design. The trick is structuring your exercises appropriately. Now, at CVP, we try to do this by (1) programming bilateral movements more frequently and at the start of a strength focussed session since they are going to work more musculature, and (2) perform unilateral training later in the session to address muscular imbalances and isolate individual limbs.