Split workouts, push-pull-legs or a body part split style routines are based on the theory that while one part or portion of your body is resting you can be working another one. This allows you to work more muscles in a workout and get more workouts into your week. Because more is more… Right?
Well when it comes to athletes for whom the gym and lifting is a tool to enhance performance (and not the sport itself, like bodybuilders and powerlifters) we find body part splits both ineffective and inefficient. Here's why:
1. Neural overload/fatigue
You may be training different muscle groups and different movement patterns butit’s still the same nervous system driving those contractions. If you don't allow days to rest between high intensity efforts that nervous system doesn't have a chance to adapt and grow. The neural fatigue from back to back sessions accumulates and ultimately interferes with your speed and skill development if you ever find time to fit in a training session on the track, court or field.
2. “Every day is kidney day”
Heavy resistance training is a stress. In the right doses it helps you adapt, get stronger, and improve. Do too much though and it's going to dip your body into an overtrained and fatigued state. Whenever we train at high intensities our body produces adrenaline. If you fail to give your body a break from the constant adrenalising effects of high intensity training and your body becomes what is called adrenally fatigued.
The other thing with training and doing lots of resistance training is the extra protein turnover. Because you're constantly breaking down and building up your muscle tissue. That puts a lot of stress on your kidneys and liver to digest and deal with thatextra protein turnover.
The people who tend to thrive the best on body split programs are those taking “special vitamins”. The type that accelerates your recovery and help you deal with those high levels of constant stress.
3. The best A-grade exercises are full body
The best exercises for athletic development tend to be multi-joint, large muscle group compound movements. Movements such as squats, Corelifts, deadlifts, lunges, arabesques, chin ups, bench press, push ups. These are all full body exercises that require large stabilising efforts from the entire kinetic chain.
4. Forearms and Grip Strength
When do your forearms get a chance to recover?
5. Core stabilisation
When do you not use your core muscles to stabilize your spine during resistance training?
6. Joint, tendon and ligament wear and tear
The big problem with doing multiple upper body days in a row is yes you might be training different patterns and working different muscles. You're still flexing and extending the same elbow and you're still stressing that same rotator cuff as it works to stabilize the shoulder.
Given tendons, ligaments and bones adapt on a 72 to a 96-yard cycle. If you put three or four workouts in five days for the same tendons, ligaments and bones that's a big hole for your body to supercompensate and adapt its way out. Then the hyaline cartilage, the stuff inside your synovial joints that makes your joints glide smoothly ; that stuff doesn't regenerate at all.
So you’re stabilising muscles fatigue (which are pre-exhausted from the day before), you start wearing and grinding on that stuff inside your joints that's going to accelerate the wear and tear and long-term damage to those joints.
7. Unpredictable soreness
For skill sport athletes (basketball, netball, soccer, darts etc) predictable levels of soreness and tightness are essential to consistent execution of skills. If you have constant fluctuating levels of soreness (say after leg day for example) the skill work you do in the 48 hours after that heavy leg session will be vastly different to the skill work you do after say arms day, that means one of the most important part of ball sports (finesse and touch based skills) is compromised and will suffer.
It’s not all bad…
Now in saying all that, don’t let perfect be the enemy of good, sometimes time constraints, team training or playing schedules mean that you have to be flexible and opportunistic in your training.
The problem is when athletes try to constantly train with heavy resistance work four to five times a week splitting up their body parts for most of the year. That fatigue and the neural overload accumulates and you're just constantly running less than one hundred percent fresh (although after a while you won’t realise and will recalibrate to the new normal).
For athletes, the goal with lifting isn't to lift as much as possible just for the sake of it. The goal is to get a return on investment because you only have so many training dollars to spend every week. If you're going to invest energy and effort into the gym you want to get a return so it makes you better on the field, the track or the court. Everything we do in the gym is directed at improving athletic performance or durability,