3 Running Intervals That Won’t Kill Your Lifting Gains

If you lift weights and also want to benefit from running, then you’re likely well aware of the potential “interference effect” between endurance and strength training. The good news? You can absolutely incorporate smart running intervals without sacrificing your strength or hypertrophy progress.

This article will walk you through three running interval protocols that minimise interference with your lifts, explain the science behind how to structure them, and give you practical programme tips to make it work.

Why running intervals can coexist with lifting

Understanding the interference effect

If you combine endurance training (such as running) and strength training, you might wonder if doing both will compromise your adaptation in one domain or the other. This question is captured by the so-called “interference effect”: the idea that concurrent endurance and strength training may blunt strength or hypertrophy gains. For example, early work by Robert C. Hickson (1980) showed that participants who did both heavy resistance training and endurance training gained less strength than the strength-only group.

More recent meta-analyses paint a more optimistic picture. For example, one review found that concurrent training had a practically negligible effect on maximal strength (standardised mean difference ≈ –0.06) and negligible effect on hypertrophy (SMD ≈ –0.01) when properly controlled. The main remaining deficit was in explosive strength/power rather than raw strength or muscle size.

Key factors that influence interference include endurance volume, intensity, proximity to strength sessions, mode (running vs cycling), and recovery.

How running intervals differ from long-steady aerobic work

When most people think of endurance work, they think of long slow runs, which incur sustained systemic fatigue, high volume, and muscular endurance demands. Running intervals—short bursts of high or moderate intensity separated by recovery—offer a different stimulus. Intervals allow you to maintain a higher intensity with less overall time, and thus less total volume and fatigue load. Interval training is well established in the running and endurance sport world for improving cardiovascular markers like VO₂ max, running economy, and speed.

Importantly for lifters, the lesser volume and shorter durations of running intervals make them less likely to induce excessive fatigue or chronic catabolic signalling that might impair lifting. The trick is to choose the right interval formats, intensities, and scheduling so that your weight training remains the priority and you don’t burn out your recovery system.

Why your lifting gains won’t have to suffer

Here are the core reasons why wisely programmed running intervals can be compatible with lifting:

• If you moderate volume and avoid doing very long or very frequent interval sessions, total fatigue remains manageable.
• If you separate your strength and running sessions by either time of day or recovery days, you reduce interference risk. Research suggests that providing sufficient time (≈ 6 hours or more) between modalities reduces interference.
• Running intervals place less structural (muscle damage) and metabolic (oxidative stress) load than long slow runs, so they are less likely to blunt strength signals such as mTOR activation. The molecular theory of interference (AMPK activation via endurance work blunting mTOR) is real in principle but appears to be overridden when volume / intensity / scheduling are well managed.
• Many concurrent training studies show additive or non-interfering results when programmed smartly.

Therefore, you can confidently add running intervals to your programme—as long as you use the right formats and timing. In the next section we’ll walk through three interval protocols designed to avoid strength-loss risk and deliver cardiovascular benefit.

3 Running Intervals That Won’t Kill Your Lifting Gains

Each of the three interval options below is selected to deliver a meaningful cardiometabolic stimulus while limiting fatigue, muscular damage, and interference with your strength sessions. Choose depending on your time availability, recovery capacity, and training phase.

Interval Protocol 1: Short-Burst Speed Intervals (Low Volume)

Structure: After warming up, perform 8–10 repeats of 15–20 seconds near maximal sprint pace (e.g., ~90-95% of max effort), with ~1.5–2 minutes easy jog/standing recovery between reps. Finish with cooldown. Total high-effort time ≈ 3–4 minutes, total session ~10–12 minutes (excluding warm up/cool down).
Why it works:

• Very brief maximal efforts minimise total fatigue and metabolic disruption compared to longer efforts.
• The long recovery interval allows near-full replenishment of phosphagen system and partial lactate clearance, reducing accumulation of fatigue.
• Because the total volume is low, structural muscle damage is minimal, preserving recovery for lifting.
  Evidence: A study comparing short vs long rest intervals in running-based HIIT found that both VO₂ max and body composition improvements occurred, with no significant detrimental effect on isokinetic strength/power when rest intervals were longer.
  Implementation tips:
• Use this interval once per week when your lifting load is heavy (e.g., strength block) so you don’t impair recovery.
• Schedule it on a day separate from heavy leg strength sessions, or at least 6 + hours after lifting.
• Keep total volume low and stop before overt fatigue. If you feel DOMS or soreness interfering with lifts, reduce or skip.
• Warm up thoroughly (5-10 min easy jog + dynamic drills), cool down 5 min.

Interval Protocol 2: Moderate-Length VO₂ Max Intervals (Time-Efficient)

Structure: Warm up 10 minutes. Then perform 4–6 repeats of 3 minutes at ~90 % of your maximal aerobic speed (or pace you could sustain for ~8-10 minutes), interspersed with 2 minutes easy jog or walk recovery. Finish with 5–10 minutes cool down. Total work time ≈ 12–18 minutes plus warm up/cool down.
Why it works:

• 3-minute work intervals place you in or near the severe intensity domain (~>90 % VO₂ max) which drives aerobic and anaerobic adaptation efficiently.
• Moderate volume means you avoid the multi-hour endurance load that could interfere with strength adaptation.
• Produces cardiovascular and metabolic benefit in a condensed time frame, leaving recovery margin for lifting.
  Evidence: For instance, a study that compared short vs long interval training found effectively improved VO₂ max with moderate intervals without high interference. Another 20-week combined endurance & strength study showed improved running economy, VO₂ max and speed with endurance + strength concurrently.
  Implementation tips:
• Best done on a lighter lifting day or upper-body strength day, so you don’t compromise fresh leg strength.
• Use only 1 session per week if you are in a heavy strength block; in lighter blocks you could raise frequency to 2 with caution.
• Ensure 48 h recovery before your most demanding leg lift day.
• Monitor your fatigue: if your squat or deadlift platform feels heavy or recovery is impaired, scale back interval duration or frequency.

Interval Protocol 3: Hill or Incline Intervals (Low Impact, Strength-Friendly)

Structure: Warm up 10 minutes. Set treadmill at a moderate incline (e.g., 6–8 %) or find a hill outdoors. Perform 6–8 repeats of 45–60 seconds uphill at high effort (e.g., ~85-90 % perceived max) followed by a comfortable jog or walk downhill/flat for 2–3 minutes recovery. Cool down 5–10 minutes. Total work time ~6–8 minutes, whole session ~15–20 minutes.
Why it works:

• Incline running reduces eccentric pounding on the joints compared to flat sprinting, lowering muscle-damage risk which helps preserve recovery for lifting.
• Uphill work emphasises glute/hamstring and general lower-body strength-endurance rather than high‐velocity damaging impact.
• The shorter work time preserves recovery capacity, and you still get cardiovascular/anaerobic benefit. Some practitioners suggest hill intervals may yield greater economy gains than flat intervals under certain conditions.
  Implementation tips:
• Especially useful in a volume-reduced phase when you want to maintain cardiovascular stimulus without heavy impact.
• Pair with upper-body strength days or rest days where legs are not heavily taxed by lifting.
• Keep downhill/flat jog recovery easy; avoid heavy leg lifting the next day if you feel soreness creeping in.
• Monitor for delayed onset muscle soreness (DOMS); if it appears in quads/hams and interferes with lifting, reduce reps or incline.

Programming Considerations for Strength + Running Intervals

Prioritise strength if your goal is lifting gains

If your primary goal is strength or hypertrophy (versus cardiovascular performance), then lifting should take priority. That means:

• Schedule your heavy lifting sessions when you’re freshest (e.g., first session of the day).
• Place running interval sessions later in the day or on separate days where possible.
• Limit running interval volume/frequency so your recovery and adaptation space isn’t crowded out by aerobic fatigue.
• If you must do both in the same day, perform the lifting first and allow at least 4-6 hours or longer before running. Research suggests separation mitigates interference.

Manage total volume and recovery

Recovery is the key to combining modalities successfully. Some specific guidelines:

• Don’t exceed two interval sessions per week if you’re in a heavy lifting phase.
• Monitor other stressors (sleep, nutrition, overall load) and ensure you’re eating enough, sleeping well, and managing life stress.
• Prioritise protein intake and carbohydrate availability to recover from both lifting and intervals.
• Use lighter or recovery days (e.g., easy jog, mobility, foam-rolling) to assist recovery rather than piling on more interval load.

Periodise your phases

A smart programme will revolve through phases, putting more or less emphasis on running intervals depending on your objectives:

• Strength block: Lifting takes highest priority; use at most one moderate interval session/week (Protocol 2) or short burst session (Protocol 1) just to maintain aerobic capacity.
• Hybrid or maintenance block: If you aim to maintain strength but improve cardiovascular capacity, you may use two interval sessions/week (e.g., Protocol 2 + Protocol 3) while maintaining 2–3 heavy lifts.
• Endurance block: If you shift emphasis toward running performance (e.g., prepping for a race), you might increase interval frequency slightly, and temporarily reduce maximal lifting volume or load to accommodate recovery.
• Deload/recovery week: Reduce both interval and strength volume to allow system recovery and super-compensation.

Monitoring fatigue and adaptation

Use these practical monitoring tools:

• Track your lifting performance: if your one-rep maxs or heavy sets are persistently down, your recovery is probably compromised.
• Use a simple rate of perceived exertion (RPE) scale and note if intervals feel much harder than usual despite consistent pacing.
• Monitor soreness, sleep quality, mood, appetite—systemic fatigue often shows up in these markers first.
• Be ready to reduce interval volume or adjust the plan if signs of overload appear.

How to Integrate with Your Current Lifting Programme

Here’s a weekly sample plan assuming you have three heavy lifting days (e.g., Monday = Upper, Wednesday = Lower, Friday = Full-Body) and want to add one running interval day without hurting gains:

Monday – Upper-body heavy lifting
Tuesday – Interval session: Protocol 2 (Moderate-Length VO₂ Max intervals)
Wednesday – Lower-body heavy lifting
Thursday – Active recovery (mobility, foam-roll) or very light jog
Friday – Full-body heavy lifting
Saturday – Interval session: Protocol 3 (Hill/incline intervals) or Protocol 1 (Short-burst speed) if your legs feel taxed
Sunday – Rest or very easy recovery jog

Key points:

• The interval sessions do not immediately precede heavy lower-body lifting—there is at least one lifting day after each interval day.
• Interval volume is controlled and limited to two sessions/week at most.
• You schedule recovery (Thursday) after the first interval session to ensure you’re fresh for leg day on Wednesday and still fresh for full-body day on Friday.
• If you’re in a peak strength block, you might drop Saturday interval entirely and only do Tuesday’s moderate interval.

Adjust volume or timing based on how your body is responding. If you notice lifting numbers stagnating or running intervals are excessively taxing, reduce interval intensity, cut session count to one/week, or alternate between high/low interval weeks.

What the Science Says About Running Intervals + Strength Gains

• A systematic review/meta-analysis of HIIT/SIT (high intensity interval training / sprint interval training) found that among healthy adults, HIIT/SIT had no significant effect on muscle strength or muscle hypertrophy when compared to non-exercise or other exercise controls.
• A study of 8 weeks of different rest-interval HIIT in running found improvements in VO₂ max and body composition with no significant detrimental effect on isokinetic strength/power when rest intervals were short or long.
• A 20-week combined endurance + strength training programme in trained runners improved running economy (oxygen cost down 4%) and VO₂ max (up 4.6%) while leg strength was maintained (though the focus was on economy rather than maximal lift numbers).
• Regarding interval design, one study found that intensified short VO₂ max interval sessions (very short, high intensity) were inferior to more traditional longer interval sessions in terms of time spent above 90% VO₂ max, suggesting that less extreme high-velocity intervals may be more efficient for adaptation.

Together, these indicate that when designed thoughtfully, running intervals do not necessarily blunt strength or hypertrophy gains—and in many cases can accompany them without major compromise.

Common Mistakes to Avoid

• Doing long steady-state runs instead of intervals: Long slow runs create large endurance load and can interfere with strength gains more than short intervals.
• Placing interval sessions immediately before heavy leg lifts: This reduces your lifting performance and recovery capacity.
• High frequency of interval sessions (3+ per week) while in a heavy lifting block: Excess load risks recovery shortfall and interference.
• Neglecting nutrition and recovery: If you run intervals and lift hard but don’t support recovery with sleep, protein, and calories, you’ll hamper adaptation in both domains.
• Not monitoring fatigue or adapting: If your lifting numbers are dropping or you feel flat, you may need to adjust interval load.

Summary & Practical Takeaways

To summarise:

• Running intervals can be effective for cardiovascular health, speed and running economy while preserving your lifting gains—provided you design them intelligently.
• Use low-to-moderate volume interval protocols (e.g., ~10–18 minutes of work) rather than long aerobic runs.
• Prioritise strength sessions, schedule running intervals so they don’t interfere with your best lifting performance, and ensure sufficient recovery.
• Monitor your lifting and running performance, soreness, RPE, and recovery metrics to adjust as needed.
• Integrate interval sessions 1–2 times per week when your goal is strength maintenance + aerobic fitness; reduce to one or none when you are in a maximal strength phase.

With the proper structure, you don’t have to choose between running and lifting—you can enjoy the benefits of both.

Bibliography

• Gibala, M. J. (2023) ‘A Perspective on High-Intensity Interval Training for Performance and Health’, Sports Medicine, 53(4), pp. 697-708.
• Kayhan, R. F. et al. (2024) ‘Effects of different rest intervals in high intensity interval training programs on VO₂ max, body composition, and isokinetic strength and power’, Journal of Obesity & Metabolic Health, 20(5), pp. 1-11.
• Rodríguez-Barbero, S. et al. (2025) ‘Effects of 20 Weeks of Endurance and Strength Training on Running Economy, Maximal Aerobic Speed, and Gait Kinematics in Trained Runners’, Applied Sciences, 15(2), 903.
• Fleckenstein, D. et al. (2024) ‘Faster intervals, faster recoveries – intensifed short VO₂ max running intervals are inferior to traditional long intervals in terms of time spent above 90% VO₂ max’, Frontiers in Sports and Active Living, 6, 1507957.
• Schumann, M. et al. (2022) ‘Compatibility of Concurrent Aerobic and Strength Training for Skeletal Muscle Size and Function: An Updated Systematic Review and Meta-Analysis’, StrongerByScience Research Spotlight (online).
• Velazquez, J. A. (2019) ‘Article Interference effect review: the grand paradox’, Exercise & Sport Nutrition Reviews, 1(8).
• Issurin, V., Lyakh, V. I. and Sadowski, J. (2020) ‘Strength Training of Endurance Athletes: Interference or Additive Effects’, Kinesiology, 52(1), pp. 35-67.
• (Note: Original Hickson R. C. study, Hickson, R. C. (1980) ‘Interference of strength development by simultaneously training for strength and endurance’, European Journal of Applied Physiology and Occupational Physiology, 45(2-3), pp. 255-263.)

Key Takeaways

About the Author

Robbie Wild Hudson is the Editor-in-Chief of BOXROX. He grew up in the lake district of Northern England, on a steady diet of weightlifting, trail running and wild swimming. Him and his two brothers hold 4x open water swimming world records, including a 142km swim of the River Eden and a couple of whirlpool crossings inside the Arctic Circle.

He currently trains at Falcon 1 CrossFit and the Roger Gracie Academy in Bratislava.