Clearing up the Repetition Speed Debate – Fast or Slow Lifting for Strength/Hypertrophy – Hams Fitness

Repetition Speed, again…..Fast or Slow Lifting for Strength and/or Hypertrophy:

The entire fast versus slow repetition debate is old and worn. Neither has been shown to be superior to the other for hypertrophy. Perhaps some difference occurs for sports specific strength training, although I have read so many conflicting studies supporting a case for either side when it comes to sports conditioning.


Yes the occasional study may show a small trend (non significant) for explosive reps being better but then another study will show the same in the other direction:

until several, repeatable studies show the same thing then we’re just pissing in the wind. Science needs to be repeatable and offer the same results for anyone for it to become fact. We have no such thing in repetition speed.
YES faster reps do expose the muscle complex to higher peak forces (for all those that shout force = mass x acceleration) but they do NOT necessarily expose the actin and myosin cross bridges to those higher forces. Lower forces on the cross bridges may be experienced.


This is a hugely important differentiation.


Fast reps create higher (peak) forces on the elastic (and thus non contractile) components of a muscle YES, but the cross bridges may not feel as much force as the actin and myosin heads do not get enough time to cycle through and make maximal strong connections…..

Slower (less than maximal) speeds allow for greater average force production produced by the actual parts of the muscle we are usually interested in…the meaty bits. Peak force is lower, force on the actual working parts of the muscle are higher.

Plyometrics (the fastest and highest force producing) exercise produces hypertrophy of the muscle as a whole (as much as weight training) but very little to none of that hypertrophy is seen in the fibres themselves…..what else can hypertrophy if not the fibres of actin and myosin then?…the elastic fibrous tissue that we are understanding more and more as science delves deeper.

Fast and slow repetition speeds will both hypertrophy a muscle. One speed will expose a muscle to very high peak forces and hypertrophy/strengthen the fibrous, elastic components (important for sports) while one will hypertrophy/strengthen the contractile elements of a muscle…the parts that are metabolically expensive, force producing and protective, the good stuff…..the parts of a muscle the majority of us that train for health and aesthetics should pay most attention to.


This will no doubt be written about a lot more but for now, this is all you need to know:


If in doubt about repetition speed, lift slower, not faster. BUT if you are happy and capable of lifting with increasing acceleration then have at it as there really appears to be little difference for healthy individuals looking primarily for hypertrophy.


Your Expert Personal Trainer, Epsom, Surrey and London,


R Ham Williams




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