Biomechanics is the structure, motion, and function of the muscles, bones, tendons, and ligaments in the body and how they work together to create movement. As it relates to exercise, this means that one must properly align joints, joint angles, and movement patterns to elicit the proper muscle contraction and target the desired muscle fibers when strength training.
For a sport such as bodybuilding, which focuses heavily on the aesthetics of the human body, understanding biomechanics is key to fine-tuning the right muscles. Let's dig deeper.
Bodybuilding focuses heavily on the aesthetics of the human body: symmetry, full muscle bellies, a lean physique, and, most importantly, size. And weight training is the most effective way to achieve that increased size of muscle fibers. Understanding the biomechanics of the body is vital to promote the desired hypertrophy and prevent injury when training for bodybuilding.
Proper biomechanics means the difference in training the biceps brachii versus the brachioradialis with the desired angle of the forearm during elbow flexion. Supination of the hand during the curl targets the biceps brachii while pronation targets the brachioradialis.
We use biomechanics to properly move through a range of motion, but it plays a larger role in injury prevention. As a trainer, you must understand proper movement patterns as well as how each small adjustment to the angles of movement will recruit different muscles. This helps to ensure your client is not overstressing their joints or recruiting undesired muscle tissue.
For example, if a client complains of elbow pain during a shoulder press, the trainer can coach them to decrease elbow flexion, which moves the dumbbells to a wider position. This will reduce the tension in the triceps, which attach at the olecranon process in the elbow.
There are many different types of training: metabolic resistance training (HIIT), endurance training, strength and conditioning, and hypertrophy training. Hypertrophy is the focus here.
Many internal factors have been found to influence the growth and breakdown of muscle tissue, but the required stressor to promote fiber growth and remodeling is the addition of an external force. When force is applied at near max or max resistance and then removed, research shows the subsequent repair of the tissue results in thicker muscle fibers versus the addition of more fibers in the same tissue.
The aesthetic training for bodybuilding requires paying careful attention to the angles of movement. Unlike functional training or powerlifting where the idea is to train heavy and functionally move weight, bodybuilding is a subjective sport. Judges assess the symmetry of one athlete in comparison to another instead of the objective ability to lift more than the next athlete on competition day. Therefore, the focus in the gym is making specific muscle groups appear larger or more prominent.
Consider the back squat as an example. A powerlifter would attempt to squat as heavy as possible, or max out. A bodybuilder will train submaximal, but will focus more on foot placement—sumo, neutral, or close—during the squat to place an emphasis on a specific head of the quadriceps while targeting the glutes and hamstring complex.
Sumo stance, feet wider than shoulders, focuses on the vastus lateralis, rectus femoris, and adductors.
Neutral stance, feet just outside of the hips, recruits vastus lateralis, vastus medialis, and rectus femoris in balance.
Close stance with feet together recruits vastus lateralis and rectus femoris.
The desire to increase the "sweep" of the quadriceps either laterally or medially will determine which stance is most beneficial. Keep in mind that research suggests there is no way to divide recruitment of the quadriceps specifically, but the muscle fibers will be used to different degrees. This promotes a change in fiber size and leg shape over time. Overall, a heavy squat is the best way to add size to the quadriceps!
Another great example is the triceps. The short head and long head of the Triceps brachii require different angles to engage. The short head is the more lateral part of the muscle group, which you can target with a simple triceps kickback or weighted dip. On the other hand, the long head is more medial on the arm, targeted with an overhead triceps extension assuming the elbows are externally rotated during the range of motion.
For bodybuilding program design, multi-joint lifts that target larger muscle groups and interval cardio training are the preferred method for hypertrophy and maximum strength. Isolation or single-joint movements hone in on specific muscles and, in most cases, this is where biomechanics will have the largest impact.
The basic movement patterns in a bodybuilding program are squat, push, and pull. You can associate many exercises with more than one pattern based on how you use them. A bench press is a push movement pattern while a deadlift could be a pull for the back or a squat variation for the legs. Examples of a pull pattern include a dumbbell row or a pull-up.
Every athlete will have lagging muscle groups. A personal trainer well-versed in proper biomechanics can use angles to target them in both multi-joint and single-joint movements. A well-designed program will also incorporate a training cycle that changes the percentage of max weight and number of reps an athlete uses, the amount of interval cardio included, and the complexity of the movements in exercise selection. The periodization, or length of time spent in each phase of training, will depend on the athlete and their goals as well as how their body responds to training.
New personal trainers have a lot to think about when entering the fitness industry. Finding a niche clientele is part of the process of establishing yourself as a reputable trainer. Staying educated and aligned with all the new research in the fitness industry is the second key to success. The addition of the ISSA Bodybuilding Certification is a great way to dive deeper into biomechanics, hypertrophy, and resistance training for a bodybuilding athlete.