Look what I found this morning on ThibArmy:
TECHNICAL EFFICIENCY
Technique work is best done with moderate weights and non-maximal reps. If the weights are too heavy (85-100% zone) you are likely to fall back onto default or compensatory motor patterns, making it harder to voluntarily make modifications to your technique. On the other hand, if the weight is too light you don’t really “feel” it properly and it will become harder to transfer the improved technique to heavier sets.
The best training zone to work on technique is 70-80%. I recommend starting closer to 70% and gradually adding weight while maintaining perfect form. Reps per set should be in the 3-5 range and the number of sets should be fairly high (5-6 or even more). But remember that none of these sets have a high level of stress because you’ll be lifting at a RPE (rate of perceived effort) of around 7. For more on RPE read Alex Babin’s articles on the subject (on the ThibArmy site).
Ideally, the frequency of practice should also be very high because frequency, not quantity, is the most important principle of motor learning. So, if you are in a technical development phase, hitting each lift 3 times per week or even more is recommended.
But remember it is important to practice the proper technique because practice doesn’t make perfect, it only makes permanent. And practicing the wrong pattern will only make that bad pattern more difficult to correct.
TECHNIQUE WORK PARAMETERS
Loading: 70-80%
Reps per set: 3-5
Sets per exercise: 5-6
Rest intervals: 2-3 minutes depending on recovery capacities
RPE: 7 – 7.5