Strength Training for Runners: when and why it changes from Parkrun (5k) to Ultra

We continue our strength training series by Coach Char - (Charlotte Milne), the Run & Strength Coach at CMF Running.  A Level 4 & 5 Personal Trainer, a strength coach for 7 years, full-time run coach for four years and lifelong running & strength training experience, Charlotte shares her strength training tips for runners.

This month Charlotte explains why and when the approach to strength training changes depending on the distance - for example training for 5K distances vs training for an ultra.

First things first: strength always matters

No matter what distance you’re training for — from Parkrun to a 50km ultra (or longer) — having some level of strength training in your week is beneficial.

Just like running, strength has a base level. Building and maintaining that base can:

• reduce injury risk

• improve running economy

• delay fatigue, especially late in races

Strength for shorter distances (e.g. 5km / Parkrun)

For 5km-focused runners, the main goal is power and explosiveness.

That means:

• plyometric exercises (jumps, bounds, hops)

• heavier lifts with lower reps

• Room to do more sessions per week or for longer sessions at the gym

Because 5km training usually involves:

• more frequent running workouts

• shorter long runs

• less total weekly time on feet

…the sessions themselves can feel harder in the moment, but recovery is quicker compared to ultra training.

Race week considerations

In the lead-up to a 5km race:

• back away from heavy or high-intensity strength work

• aim to keep legs feeling fresh and responsive

• light activation or mobility-based strength can still work well

Strength for ultra running

Ultra strength training looks different — the focus shifts from power to strength and conditioning.

The goals here are:

• building conditioning on the legs

• improving fatigue resistance

• preparing the body for long hours of repetitive movement

• supporting stability and agility on technical trails

Strength training can also help with trail-specific demands, like:

• uneven terrain

• descents

• balance and coordination

Early training phase (base phase)

In the early stages of an ultra build:

• heavier weights

• simple but effective compound movements

• lower reps

Key areas to prioritise:

• lower body

• core

• upper body

• Basically, everything is important 😉

A strong core and strong glutes help you maintain form and run more efficiently for longer.

Key training weeks (specific phase)

As you move into your key ultra weeks (such as 3-5 weeks out)

• reduce load

• increase reps (around 6–10 reps)

• focus more on muscular hypertrophy than max strength

You can still reintroduce heavier lifting (such as 2 weeks out)

• after key blocks

• second week out from race day but only if your energy is feeling good and the strength work adds to your training and doesn’t deplete you.

• avoid heavy lifting close to race week

Why upper body matters more for ultras

Upper body strength becomes more important in ultra running because:

• posture becomes harder to maintain over long durations

• better posture = better breathing

• better breathing = delayed fatigue

• If you’re a pole user, then building some upper body strength will be beneficial

A note on ultra variability

Ultra training is more complex to prescribe because:

• one runner might finish a 50km in 3.5–5 hours

• another might take 6–7.5+ hours

• terrain, elevation, and technicality massively change the demands

So this could mean the intensity, duration and specifics of the strength training could vary depending on the time and intensity that you’re racing at.

Always consider:

• your experience with strength training

• your lifting background

• how well you recover

Big picture takeaway

• Strength training is most valuable in the base phase.This is where you build resilience to strength training and gradually train yourself out of getting DOMS every time you lift. At the same time, if you do get DOMS, it’s far less of an issue — base phase sessions aren’t race-critical, so a bit of soreness won’t derail key workouts.

• More variety can be useful early on

• Longer strength sessions or occasional HIIT-style work can be appropriate

• Lifting heavy can be appropriate for both 5k or ultra distances but there are some differences in how often and when do it.

• As race specificity increases, strength becomes more supportive and less fatiguing

• Do what you enjoy and what you’ll be most consistent with. Don’t force yourself to do something you find boring — you’re far less likely to stick with it long term, and consistency is what actually delivers the benefits.

Like always guys- #havefun with your strength training and in your training as a whole. Strength training can have a lot of benefits to your running and in life so go explore how strength training can help you!

Other Resources

• YouTube: https://www.youtube.com/@trailgirlcharlotte

• Instagram: @trailgirlcharlotte

• Book a Call: https://www.cmfrunning.nz/pages/free-coach-call