No, Push Pull Legs is NOT the best training split!!!

Technically, there is no training split that is the "best". The productivity of a certain training split comes down to how the trainee uses and customises that split. However, generally speaking, push-pull-legs is probably the most inefficient training split for any level of trainee, but especially beginners (amongst whom it is the most popular).

The push-pull-legs split is based on the muscles responsible for certain movement patterns. On a "push" day, you target the chest, shoulders and triceps, which are the muscles largely responsible for any pushing movement. Similarly, the "pull" day is reserved for the back and biceps, and the leg day, well, for the legs. There are two main problems I have with this split: 

    1. This split is commonly executed incorrectly

    2. It is generally inefficient

1. PPL is usually executed terribly!

Like I said, there is no training split that is superior on its own. Training splits only shine when they are executed correctly; and the same holds for PPL! When you are training 6x a week, the higher frequency means that you MUST reduce your volume so that a high intensity of training can be maintained without impeding recovery. 

All too often do I say cookie-cutter PPL routine with 7, 8 or 9 exercises per workout. This is WAY too much volume for a beginner or intermediate lifter, given that you are training at a pretty high intensity(1-2 reps short of failure on most exercises). Advanced trainees would just waste their time doing all of this junk volume 6 times a week. A good PPL split would only have around 4 exercises per session. Even to maintain this, recovery MUST be on point. This means at least 8 hours of sleep and a consistent and sufficient calorie surplus and balanced diet.

2. PPL is an inefficient split

The main advantage of a PPL split is its high frequency. Each muscle group is being trained 2x a week. However, this is not unique to the PPL split! Splits like upper/lower 4x a week and full body 3x a week offer similar or even higher frequencies of training each muscle group WHILST allowing for more rest days and thus more recovery. So a PPL split has you spending endless hours in the gym for inferior results. Many trainees think they can get more recovery by doing Push/Pull/Legs/Rest and then repeat. However, this removes the high frequency of the split, which is a major reason someone would choose it in the first place! This makes the PPL split an inefficient allocation of time and energy, and most trainees would benefit from switching their split to upper/lower 4-6x a week or full body 3x a week.

Finally, I wanted to provide an example of what a good PPL split looks like. Although I just slandered the split, I do believe it has some value since it allows for relatively more volume to be directed to each muscle group. Here is what a pretty decent PPL split would look like for an intermediate to advanced trainee looking to gain size and strength:

Additional Notes:

    - The pull day is put before the push day to minimize lower-back fatigue during leg days IF you choose to use a free-standing rowing variation on the pull days.

    - A rest day should be taken after the final leg session. You could have a rest day after every pull/push/legs cycle for better recovery, although this would decrease frequency.

    - Deload from this program every 12-18 weeks

    - A and B category exercises can be rotated every 5-6 weeks, whereas C exercises can be rotated    every 3-4 weeks

    - Below are some suitable exercise substitutions that you can make

Exercise Substitutions:

    - Horizontal Row - Dumbbell Seal Row, Pronated Inverted Row, Seated Cable Row, Neutral Grip Inverted Row

    - Horizontal Press - Bench Press, Larsen Press, Weighted Pushup, Weighted Dip, Incline Bench Press, Pin Bench Press, Bottoms Up Dip, Pause Bench Press

    - Vertical Press - Strict Press, AD Press, Push Press, Z Press, BTN Press, Trap Bar Overhead Press

    - Squat Variation - High Bar Back Squat, Front Squat, Pause Back Squat, Low Bar Squat, SSB Squat, Zombie Front Squat

    - Deadlift Variation - Conventional Deadlift, Sumo Deadlift

    - Knee Flexion - Seated Leg Curl, Nordic Curl, Glute Ham Raise   

    - Core Exercise - Weighted Plank, Bodysaw, Standing Ab Wheel Rollout

    - Heavy Hold - Suitcase Hold, Pallof Hold, Front Squat Hold

And there you have it! This is a damn decent program that you could choose to run if that was your wish. I personally would never run a program like this since the frequency is just not ideal for the amount of work you are putting in, in my opinion. However, this is the way I would go about programming a PPL split if I had to. Enjoy!