Hi there and welcome to post 45 of Strength & Conditioning For Therapists. How are things with you today? Did you enjoy last week’s post? Hopefully you felt reassured that not all is lost during this period of lockdown, even if you do stop exercising. This week we’re going to take a more detailed look at how to avoid detraining and limit strength losses in lockdown, plus a little on hypertrophy.

Effects of Detraining On Muscle Strength

So last week we looked at the research that illustrated that over a period of 6-weeks to 3-months of detraining i.e. cessation of structured training, losses to strength might approximate 14-25% (knee extensor strength: Blocquiaux et al. (2020); Kalapotharakos et al. (2019)).

The good news is that if you’re coming from a relatively good baseline of strength and previously trained for say 12-weeks, the gains that you made will only likely be partially lost over an equivalent period of detraining. Good to know as we approach week 5 of lockdown. As we said last week, not all is lost.

Detraining; Why Do We Get Weaker?

What happens when we remove the training stimulus? Well clearly there’s no longer the need to accommodate the same loads through the tissues, therefore, the body adapts to the ‘new’ less stressful environment and the body deconditions.

So, what do we lose and how can we avoid detraining? The initial gains that we make in a novel strength training programme are neural. That means the signaling to the musculature (central drive) increases, there’s an increase in activation of fast twitch motor units, improved synchrony of firing of motor units etc. This occurs prior to the morphological changes (hypertrophy, increased tendon stiffness) that are observed. So does this mean that we lose the neural adaptations first during detraining, or is it the cross-sectional area?

There’s a bit of debate on this. Some report that the prevailing mechanisms for strength loss in the initial phases of detraining are neural i.e. that size per se doesn’t change, it’s the central drive, activation etc. Others report the contrary.

Have a look at the results of this study by Kubo et al. (2010) [below]. It was a training-detraining study, in which they monitored changes to strength plus neural and morphological factors.

So it took a couple of months to see any changes in muscle strength, which we might expect as the specificity wasn’t entirely aligned to optimise strength gains. As predicted the mechanisms for these gains were neural (mEMG = muscle electrical activity) and it wasn’t until the 3-month mark that changes in tendon stiffness and muscle cross-sectional area (CSA) were noted. So far, as we would expect, right?

Here’s the unexpected result; during the 3-months of detraining, there were no changes to muscle strength i.e. participants maintained their new strength levels. …. But there was a reversal in the changes to CSA and tendon stiffness. Whilst we might expect the tendon properties to revert back to baseline in a couple of months, perhaps, a change in muscle CSA without changes to neural parameters is surprising. Well it would be if strength losses were observed.

Are Strength Gains Maintained?

What does this mean? Can we use this information in strategies how to avoid detraining and limit strength losses? Taken in isolation, the results of this study suggest that there’s the potential for preservation of muscle strength during a 3-month period of deconditioning, which is due to the retention of neural adaptations. Changes to muscle CSA, however might be lost.

These data are contrary to what I presented last week whereby even a 6-week period of detraining resulted in strength losses. This discrepancy is likely influenced by several factors, which in my view includes the characteristics of the resistance training programme. Kubo et al. (2010) trained the knee extensors isometrically at a single joint angle and at a specificity that was not optimised for muscle strength gains. They measured strength in the same manner – isometrically at the same joint angle; what we don’t know is if the specific adaptations were retained at different joint angles and, or, during dynamic contractions.

This is good to know, but we need to be cognisant of the other literature employing more dynamic/realistic training or rehabilitation programmes followed by detraining. These typically show a loss in strength, and where measured the contributing mechanisms are likely a combination of neural (perhaps mainly) and morphological factors (less so in the short term). I want to avoid at this point reviewing the literature on this topic and refocus on what we need to do to attenuate strength losses.

Effects Of Re-Training On Muscle Strength

Okay, to refocus, we discovered last week that:

  • 1. If you find the time and and inclination to recommence training following a period of disengagement, you can most definitely make back those losses. (YAY!)
  • 2. Regain of these strength losses might take only half the time (DOUBLE YAY!)

What if we wanted to keep training and try limit the losses? Is this possible? How to avoid detraining and how much (of what) do we need to do?

I think there’s a little more volume of research on this topic on cardiovascular (CV) fitness versus muscle strength and hypertrophy, but here’s my take on it.

How To Avoid Detraining During Lockdown

Garcia-Pallares et al. (2009) conducted a nice study looking at reduced training volume of the CV fitness and strength of elite kayakers. Their typical training volume comprised of 7 hours CV work per week and 2.5h of strength work per week, representing 10-15 and 3 sessions, respectively. They then reduced this to 5 weeks of only 1 session of strength: 3×10 reps (of 12RM load) in the bench press, prone bench pull and squat exercises, and 2 endurance sessions (1 kayak, 1 run) each of 40 mins.

At the end of the 5 week period, the control group who did no training lost 8-9% of upper body 1RM strength (bench press and bench pull) whereas the reduced training group only lost 3.4-3.9%. Again, the specificity wasn’t such to optimise strength gains, however, this shows that approximately 20% of the training volume was sufficient to reduce the strength losses by over half! (Incidentally, this was the same for CV fitness parameters).

In answer to our ‘how to avoid detraining and limit strength losses’ question, if you can’t safely generate the overload required to train strength, this study shows that there is some merit in working in a more hypertrophy RM range to attenuate losses in strength.

Let’s take a look at another study. Schoenfeld et al. last year (2019) investigated the effects of training volume on muscle strength and hypertrophy. Again training at 8-12RM is not optimal for strength gain, but it is useful for the current context as most of us aren’t able to access a gym to achieve the overload. Look at the table below where I’ve tabularised the results and the volume of work per muscle group per week.

Some of the key points to note here are that 8-12RM will still generate some strength gains, albeit not optimal (as we’ve said before). Also the volume of training is a key factor required to stimulate the hypertrophic response (5 sets > 3 sets). There are many things we can discuss here, but in the current context, for the preservation of muscle strength during lockdown, or how to attenuate losses in the absence of very heavy loads the message is work to failure at the sub-optimal loads.

Finally, let’s look at another study – only just released as an online first copy. Kubo et al. (2020) evaluated the effects of volume-matched training at 4RM; 8RM and 12RM bench press training. Well, when you tot up the number of reps performed, it’s not quite volume matched, but anyways, it’s a lot closer than many studies. So, what did they find..? Again, it’s volume not load that’s the most important factor to elicit hypertrophic response (see below); there were no differences in muscle volume between the 3 conditions.

Load did matter when it came to strength gains though – as we would expect. 12RM volume matched training elicited only half of the strength gains compared to the 4RM and 8RM conditions. There are several other studies that we can mention that show similar things, but let’s sum up here and get the take-home messages.

Summary

We’re in lockdown (or most of us are) with limited ability to optimally strength train. What does the research tell us about how our neuromuscular systems are going to respond and how to avoid detraining?:

  • You (or your patients) are unlikely to lose all the gains in muscle strength and size accrued over the past few weeks and months if you cease training for the equivalent period, as long as we’re not in this situation for the rest of the year!
  • Recommence training and you (or your patients) can potentially get back to their baseline prior to COVID-19 in perhaps half the time of the initial training programme.
  • Continue training at a high intensity and as little as 20% of your normal workout volume may be sufficient to cut your performance losses in half (compared to if you stopped training all together)
  • Specificity is important, but work to failure to limit losses. Unless you have a super home-gym, the lighter loads that you’re able to fashion performed to failure will help preserve strength losses (the amount is likely due to the resistance training history of the person), or in some perhaps induce strength gains.

And finally…

  • Don’t forget the interference effect. If you massively ramp-up your endurance training volume, it can interfere with strength adaptations (read about that here). At this point, unless you’re an elite strength athlete, I don’t think this will matter too much.
  • Be safe and thank about injury risk. Be creative in your exercise design to make them challenging, but not at the expense of safety – single-leg squats holding your child probably isn’t the best idea 😉

Check out the course listings for after June 2020 – hopefully we’ll have returned to normal following the COVID-19 pandemic by then.

References

  • Schoenfeld et al. (2019).Med. Sci. Sports Exerc.51(1), 94–103 (available here)
  • Garcia-Pallares et al. (2009) J Sports Sci Med 8(4):622-8. (Available here)
  • Kubo et al. (2020). J Strength Cond Res (Abstract here)