Mitigating the Interference Effect

I think the way to look at it is to step back. If absolute speed and power development are your goals we need to train in such a way where absolute speed and power are trained with best practices. This means regular exposures to maximal or near maximal intensities without the constraints of fatigue. The trouble is, this type of work is very demanding and needs adequate rest following training these qualities.

We also need to recognize that low and even moderate intensity work helps enhance overall fitness and work capacity, allows athletes to recover faster, and drives sympathetic:parasympathetic balance…all of which can play an important support role for speed and power adaptations if the requisite speed and power training stimulus has been applied. The problem here is if we do too much of this work, or do it at the wrong time, we run the risk of introducing an interference effect and blunting the adaptations of high neuromuscular demand work.

So how do we maximize the benefits and minimize the costs of these two training types?

Alternating high neuromuscular demand days and low neuromuscular demand days allows us to create as much time or polarity of stimulus as possible between sessions. This helps ensure that the training stimuli that the athlete will adapt to in the period between one session and the next is as ‘clean’ as possible. There’s certainly still some interference effect but any negatives are easily outweighed by the positives of the lower intensity work as long as the sessions and pairings are designed appropriately. And in the long run, increasing work capacity via the lower intensity work might actually help the athlete to handle higher volumes of the high neuromuscular demand work so a stronger signal (of the high neuromuscular demand work) can be sent. I try to design training plans for speed power athletes with the following in mind:

1. Speed-power athletes need regular exposure to the high neuromuscular demand work that will produce the specific adaptations that will increase performance
2. High neuromuscular demand work cannot be trained too frequently for fear of overtraining / overreaching
3. Lower intensity work has many benefits in a support role for higher intensity work
4. Too much low and moderate intensity work could potentially blunt the adaptations of high intensity work

We need to balance the pros and cons of the above points which ultimately ends up looking like an alternation of training means and methods to increase stimulus polarity between days.

And for the second part, the level of conditioning challenge would definitely effect the interference effect. I’ve found complete or near complete rest is necessary when the objective is absolute speed and power.

As for alternation of body parts this could conceivably work and sports like powerlifting and a couple notable Pump & Run athletes have used schemes that take advantage of this notion. From the standpoint of the stimulus on the muscular system, you could probably keep the signal ‘clean’ by splitting body parts but the much of the nervous system is shared across body parts so you couldn’t separate it completely.