HOW TO IMPROVE ENDURANCE FOR LONGER DISTANCES

Published: 01/12/2025 | Written By: Fin Dearsly

From being a national tennis talent to competing in HYROX, sport has been – and probably always will be – a part of Fin Dearsly's life. These days, however, he's taken on another challenge in his already busy schedule: endurance running. Yes, just that. If it’s something that’s also part of your life but you’re not quite sure how to improve your endurance for longer distances, stick around. From what it means to top tips, in this piece, the Sports Direct ambassador breaks it all down for you.

When most people think of endurance, they think of distance – in other words, how far you can run before you stop. But true endurance isn’t just about going further. It’s about how efficiently you can sustain effort and performance over time. It’s your body’s ability to maintain pace under fatigue, and your mind’s ability to stay composed when everything starts to hurt.   

When I was preparing to run 350k along the River Thames last October, I realised endurance is less about mileage and more about management – managing energy, recovery, and discipline. Understanding this shift in focus was a game-changer because it completely changes the way you approach training.

WHY LONG RUNS ALONE AREN’T ENOUGH 

One of the biggest lessons I learned early in my ultra training was that endurance doesn’t come from running alone. Long runs are important, sure, but the body can only handle so much impact before it starts to break down. True endurance is built by strengthening all the systems that support running, not just the legs. This is where strength, mobility, and recovery come into play: 

• Strength builds resilience – stronger legs and hips absorb impact better and maintain form deep into a run. 

• Mobility keeps movement efficient – less energy wasted means more endurance over time. 

• Recovery is where adaptation happens – endurance is built when you recover properly from hard work. 

Over the last few months, I’ve learned that the key to consistent training is balancing the load. I still run approximately 100k a week, but I complement that with gym sessions designed to build muscular endurance and durability. In other words, it’s not just about quantity – it’s about quality and balance. Here’s what a typical week of training has looked like during this prep: 

Plan

MONDAY

AM – Lower Body Strength

• Focus: Build strength and power for running efficiency.

• Exercises: Squats, deadlifts, lunges, hip thrusts, calf raises (3-4 sets of 6-12 reps depending on intensity).

• Tips: Maintain proper form to avoid injury. Include a short mobility warm-up for hips, hamstrings, and ankles.

• Goal: Improve running economy and injury resilience.

PM – Zone 2 Erg (Cycling/Rowing/Low-impact Cardio)

• Focus: Aerobic conditioning at ~60-70% of max heart rate.

• Duration: 45-60 minutes.

• Tips: Keep a steady pace, ensure smooth, efficient technique, and avoid going into higher heart rate zones.

• Goal: Build aerobic base without taxing legs too heavily after strength training.

TUESDAY 

AM – Upper Body Strength 

• Focus: Build upper body strength for posture, stability, and better running form 

• Exercises: Pull-ups/lat pulldowns, bench press or push-ups, rows, shoulder presses, core work (3–4 sets of 8–12 reps) 

• Tips: Maintain proper form to avoid injury. Include a short mobility warm-up for shoulders and back. 

• Goal: Support posture under fatigue and improve overall muscular balance. 

PM – 10–12k Intervals 

• Focus: Speed and lactate threshold 

• Structure Example: 5×1 km at 10k pace with 2–3 min easy jog recovery OR 8×800m at slightly faster than 5k pace 

• Tips: Warm up for 15-20 min, include dynamic stretches, finish with a 10-min cooldown 

• Goal: Improve running economy and VO₂ max 

WEDNESDAY – REST DAY 

• Focus: Recovery and regeneration 

• Optional: Light mobility, stretching, yoga, or a short walk 

• Goal: Allow muscles and nervous system to recover to maximise performance later in the week 

THURSDAY 

PM – 5-7k HYROX Track Session 

• Focus: HYROX-specific conditioning (strength-endurance + running). 

• Structure: Combine running with functional movements (sled push/pull, burpees, rowing, wall balls). 

• Tips: Keep intensity moderate to high, track work/rest ratios, prioritise technique on strength movements. 

• Goal: Develop functional endurance, muscular stamina, and metabolic conditioning. 

FRIDAY 

AM – Lower Body Strength 

• Focus: Same as Monday but can vary exercises or reps to target different muscle groups or power vs. hypertrophy 

• Examples: Romanian deadlifts, Bulgarian split squats, step-ups, glute bridges 

• Goal: Build strong legs to handle higher weekly mileage 

PM – 15k Tempo Run 

• Focus: Lactate threshold development 

• Pace: “Comfortably hard,” around 80-85% max heart rate or slightly slower than 10k pace 

• Tips: Warm up for 15-20 min, maintain consistent pace, cool down 10 min 

• Goal: Increase sustainable speed for longer distances. 

SATURDAY 

AM – 30-35k Long Run 

• Focus: Aerobic endurance 

• Pace: Zone 2, conversational pace 

• Tips: Practice fueling (gels, hydration) and pacing strategies for long events 

• Goal: Improve aerobic base, muscular endurance, and mental stamina

SUNDAY 

AM – 35-40k Long Run 

• Focus: Back-to-back long run for ultra-endurance or HYROX-specific endurance training 

• Pace: Zone 2, comfortable pace, slightly slower than Saturday if fatigued 

• Tips: Prioritise hydration, nutrition, and post-run recovery (stretching, foam rolling, ice bath if needed) 

• Goal: Build resilience and condition the body for high-volume weeks 

PRACTICAL TIPS FOR ENDURANCE TRAINING 

So, how do you put this into practice? If you’re training for a long-distance event, here’s what I’ve found works best: 

1. Pace early, push late. Don’t get caught up chasing splits in the first half. Endurance is about patience.

2. Prioritise recovery. Sleep, nutrition, and low-impact Zone 2 sessions (bike or rower) are as important as your long runs.  

3. Build gradually. Increase weekly mileage by no more than 10%. The goal is consistent progression, not sudden jumps.  

4. Use ergs. To further develop your aerobic base without putting extra stress on your joints, erg machines like bike, ski, or rower are perfect. I spend hours on these each week in Zone 1 or Zone 2 heart rate zones. 

5. Strength isn’t optional. Two to three full-body sessions a week will do more for your endurance than an extra jog ever will. 

Training for the Thames Ultra taught me that endurance isn’t built in a single heroic session – it’s built quietly, over weeks and months of showing up. It’s found in the discipline to recover, the patience to build slowly, and the resilience to keep going when motivation fades. Endurance isn’t just about how long your body can keep moving. It’s about how long your mind can keep believing.