Resistance Training Drills for IM Power Development

The Individual Medley presents a unique physiological challenge unlike any other event in competitive swimming. Where a single-stroke specialist can dedicate the vast majority of their power development toward one specific muscular and technical pattern, an IM swimmer must develop meaningful power across four biomechanically distinct strokes — each of which recruits different muscle groups, different force-application angles, and different rates of fatigue. A swimmer who is powerful in butterfly but underdeveloped in breaststroke-specific musculature will find their overall IM time capped by their weakest leg, regardless of how dominant they are in the other three strokes.

Resistance training — whether performed in the water using drag-inducing or resistance-adding equipment, or on land through targeted strength work — is one of the most effective tools available for building the specific power an IM swimmer needs across all four strokes. Unlike pure aerobic or technical work, resistance training directly targets the force-production capabilities that allow a swimmer to generate more propulsion per stroke, hold technique together under fatigue, and execute powerful starts, turns, and finishes even in the closing stages of a demanding 200 or 400 IM.

This article covers the physiological rationale for resistance training in IM-specific power development, then provides a comprehensive set of in-water and dryland resistance drills organized by stroke and by movement pattern, along with guidance on how to structure this work across a training week and a season.

Why IM Swimmers Need a Distinct Approach to Power Development

Four Strokes, Four Different Power Demands

Each of the four competitive strokes places different demands on a swimmer's musculature and force-production patterns:

Butterfly demands significant upper-body and core power, particularly through the chest, shoulders, and lats during the pull, combined with a powerful, whip-like core-driven dolphin kick. The double-arm recovery and simultaneous pull pattern also place unique demands on shoulder stability and power under a wide range of motion.

Backstroke relies heavily on lat and shoulder power for the pull, combined with rotational core strength to support the body roll that underlies an efficient stroke, and a flutter kick that, while less power-dominant than the fly kick, still contributes meaningfully to overall speed and body position.

Breaststroke is arguably the most leg-dominant of the four strokes, with the whip kick generating a substantial portion of overall propulsion, supported by a shorter, more explosive arm pull compared to the other strokes, along with a uniquely important pull-out sequence that has its own specific power demands.

Freestyle demands sustained rotational core power and a continuous, alternating pull pattern, supported by a flutter kick that in most swimmers contributes more to balance and body position than to raw propulsion, though it still requires meaningful power, particularly during sprint segments.

Because these four demands are so distinct, a resistance training program built purely around general swimming fitness — without specific attention to each stroke's unique power requirements — will tend to leave gaps, often most visibly in whichever stroke is a swimmer's natural weak point.

The Fatigue-Power Relationship in Longer IM Events

In the 400 IM specifically, swimmers must generate meaningful power not just at the start of the race, but through each of the four 100-meter legs, with fatigue accumulating throughout. Since breaststroke — often physiologically the most taxing of the four strokes for many swimmers — comes in the third position of the IM order, swimmers frequently experience their greatest power and technique breakdown precisely when they can least afford it. Resistance training that specifically builds the strength and power endurance needed to sustain technique under this kind of accumulated fatigue is therefore especially valuable for 400 IM specialists.

Resistance Training Builds the Force Base That Technique Alone Cannot

While technical efficiency (discussed at length in most swim training contexts) determines how effectively a swimmer converts their force output into forward speed, resistance training addresses the separate but equally important question of how much force a swimmer is capable of producing in the first place. A swimmer with excellent technique but a limited underlying force base will hit a ceiling on their potential speed that no amount of additional technical refinement alone can overcome. Resistance training raises this ceiling, giving a well-trained technique more raw power to work with.

In-Water Resistance Tools and Their Applications

Drag Equipment (Parachutes, Drag Suits, Drag Socks)

Drag equipment increases the resistance a swimmer must overcome to move through the water, forcing greater force production per stroke cycle to maintain a given speed. This is one of the most versatile and widely used categories of in-water resistance training, since it can be applied to any of the four strokes and can be scaled in intensity by adjusting the size of the parachute or the amount of drag material used.

Drag Parachute Sets by Stroke Attach a small-to-moderate resistance parachute and swim repeats of each of the four strokes — for example, 4 x 25 fly, 4 x 25 back, 4 x 25 breast, 4 x 25 free, with the parachute attached throughout — focusing on maintaining stroke technique and rate as much as possible against the added resistance. This builds stroke-specific power across all four strokes in a single, efficiently structured set.

Parachute-Assisted IM Broken Swims Swim a broken 200 IM (50 of each stroke, with brief rest between each 50) with the parachute attached for the first 25 of each 50, removing it for the second 25. This trains the swimmer to generate power against resistance and then feel the corresponding "release" of speed once the resistance is removed — a training effect sometimes referred to as overspeed or contrast training, which can improve a swimmer's sense of stroke power and rate.

Resistance Bands and Stretch Cords

Stretch cords anchored to the starting block or pool deck allow swimmers to perform stroke-specific pulling motions against direct, adjustable resistance, either in a stationary position or while attempting to swim forward against the cord's increasing tension.

Stationary Stroke-Specific Pull Drills Anchor a stretch cord and have the swimmer perform the pulling motion of a specific stroke — fly, back, breast, or free — against the cord's resistance while remaining largely stationary in the water. This isolates the pulling muscles specific to each stroke and allows for high-repetition power work without the added complexity (or fatigue cost) of full-stroke swimming. Perform 3–4 sets of 10–15 repetitions per stroke, focusing on generating power throughout the entire length of the pull.

Resisted Swim-in-Place Drill With a stretch cord providing continuous resistance as the swimmer attempts to swim forward (essentially remaining in place, or moving very slowly, against the cord's pull), swimmers can perform short, high-intensity bursts of full-stroke swimming for each of the four strokes, building both power and specific technique-under-load simultaneously. Bouts of 15–20 seconds per stroke, with full recovery between attempts, work well for this drill given its high intensity.

Paddles

Hand paddles increase the surface area of the hand, requiring greater force production and increased feel for the water throughout the pull. Because paddles place additional stress on the shoulder joint, they should be introduced carefully and are generally more appropriate for post-pubescent or more experienced swimmers with well-developed shoulder stability, though various paddle sizes exist to scale the intensity for different populations.

Paddle Sets by Stroke Incorporate paddles into stroke-specific pull sets — such as 6 x 50 of each stroke's pull pattern (using a pull buoy where applicable to remove the kick) with paddles — focusing on a complete, powerful pull from catch through finish for each of the four strokes.

IM Paddle Broken Swim Swim a broken 200 IM with paddles throughout, focusing on maintaining a strong, complete pull across all four strokes even as fatigue accumulates through the swim. This combines stroke-specific power work with race-order IM training, building specific strength exactly where it will be needed in competition.

Fins

While fins are more commonly associated with kick-specific speed work than pure resistance training, certain fin-based drills can be structured to build power rather than simply speed, particularly when combined with other resistance tools or used for explosive, short-burst efforts.

Explosive Fin Kick Sets by Stroke Using fins, perform short (10–15 meter) maximal-effort kick sets in each of the four strokes' respective kick patterns (dolphin kick for fly, flutter kick for back and free, whip kick for breast), focusing on generating maximum power and speed. While the fins reduce resistance compared to barefoot kicking, the maximal effort and short duration of these sets still build meaningful power, particularly when performed as a demanding, high-intensity addition to a broader resistance-focused practice.

Pull Buoys and Ankle Bands (Isolating the Pull)

Combining a pull buoy (which floats the legs and removes the kick from the equation) with an ankle band (which binds the ankles together, further eliminating any kick contribution) allows swimmers to isolate the arm pull entirely, placing the full propulsive burden on the upper body and core. This is a valuable tool for building pure pulling power and pulling-specific muscular endurance across all four strokes.

Isolated Pull Sets by Stroke With pull buoy and ankle band in place, swim 4 x 50 of each stroke's pull pattern, focusing on generating full propulsion from the arms and core alone. This is particularly valuable for breaststroke and butterfly, where the pull pattern is significantly different from the more continuous, alternating pull of backstroke and freestyle, and therefore benefits from dedicated, isolated attention.

Dryland Resistance Training for IM Power

While in-water resistance tools are valuable for building stroke-specific power in a directly transferable context, dryland strength training remains an essential complement, particularly for building the foundational force capacity, injury resilience, and power output that in-water training alone often cannot fully develop, especially in younger or developing swimmers.

Upper Body and Pulling Power

Lat Pulldowns and Pull-Ups Directly targets the latissimus dorsi, one of the primary propulsive muscles across fly, back, and free. Building general lat strength and power through both wide-grip and narrow-grip variations supports the pulling power needed across multiple strokes simultaneously.

Cable or Band Rotational Pulls Mimicking the diagonal, rotational pulling pattern found in freestyle and backstroke, these exercises build power through a movement pattern that more closely resembles actual swimming mechanics than a purely vertical or horizontal pulling motion.

Medicine Ball Chest Pass and Overhead Throw Particularly relevant for butterfly's simultaneous, explosive pulling pattern, these explosive medicine ball exercises build the rapid force production needed for a powerful fly pull, in a movement pattern and speed that more closely mirrors the actual demands of the stroke than slower, traditional strength exercises alone.

Core and Rotational Power

Medicine Ball Rotational Throws Directly supports the rotational core power needed for backstroke and freestyle body roll, as well as the whip-like core engagement that drives an efficient butterfly undulation. Performing these throws explosively, rather than as a slow, controlled strength exercise, better matches the speed demands of actual stroke mechanics.

Cable Woodchoppers Another rotational core exercise that builds the diagonal, cross-body strength pattern relevant to freestyle and backstroke rotation, performed both high-to-low and low-to-high to address rotation in both directions.

Stability Ball or Suspension Trainer Core Work Exercises such as stability ball rollouts or suspension trainer (TRX-style) pikes and knee tucks build the anti-extension and anti-rotation core strength that supports a stable, powerful body line across all four strokes, particularly important for maintaining technique under the fatigue present in longer IM events.

Lower Body and Kick-Specific Power

Squats and Squat Jumps General lower-body strength and explosive power work supports the powerful leg drive needed for starts and turns across all four strokes, as well as general kick power, particularly relevant for the whip kick central to breaststroke propulsion.

Resistance Band Ankle Flexion/Extension Work Targeting the specific ankle flexibility and strength needed for an effective flutter and dolphin kick, this more isolated exercise supports kick power in fly, back, and free specifically.

Lateral Band Walks and Hip Abduction/Adduction Work Particularly relevant to breaststroke's unique whip kick, which relies heavily on hip rotation and the specific muscles involved in hip abduction and adduction, this type of targeted lower-body work supports both power and injury prevention for the breaststroke-specific kick pattern.

Explosive, Power-Focused Full-Body Work

Box Jumps and Depth Jumps Building general lower-body explosive power that translates directly to more powerful starts and push-offs from the wall across every stroke and transition in the IM.

Kettlebell Swings A hip-hinge-dominant explosive exercise that builds posterior chain power relevant to both the leg drive off the wall and certain aspects of core-driven stroke power, particularly in butterfly and freestyle.

Structuring Resistance Training Across a Training Week

Given the number of different tools and exercise types outlined above, it's important to structure resistance training thoughtfully across a training week and season, rather than attempting to incorporate everything at once.

Early Season (Base-Building Phase). Emphasize foundational dryland strength work (squats, pull-ups, general core stability) combined with moderate in-water resistance work (light parachute or paddle sets), focusing on building a general strength base before introducing more specific, high-intensity power work.

Mid-Season (Power Development Phase). Increase the specificity and intensity of both dryland and in-water resistance work, incorporating more explosive dryland exercises (medicine ball throws, box jumps) alongside more targeted in-water resistance sets (stroke-specific paddle and parachute work, isolated pull sets), with resistance training generally structured 2–3 times per week alongside regular technical and aerobic pool training.

Taper Phase (Pre-Competition). Significantly reduce volume of both dryland and in-water resistance work while maintaining some light, low-volume power maintenance work (a small number of explosive, low-repetition exercises) to preserve strength gains without accumulating additional fatigue heading into competition.

A sample mid-season week might include two dedicated dryland strength sessions (built around the exercise categories above, generally scheduled after pool practice or on a separate training block to avoid excessive same-day fatigue before key swim sets), combined with two or three in-water resistance-focused pool sets integrated into regular practice, generally scheduled earlier in a training week when swimmers are less fatigued and better able to execute resistance work with good technique.

Monitoring Progress and Avoiding Overtraining

Because resistance training — both in-water and on land — places additional stress on a swimmer's body beyond regular swim training volume, it's important to monitor for signs of excessive fatigue or overtraining, particularly in younger or developing swimmers whose bodies are still growing and adapting.

Useful monitoring practices include tracking stroke count and technical quality during resistance-focused pool sets over time (declining technical quality despite consistent or increasing resistance load may indicate a need for more recovery), periodically testing sprint or power benchmarks (such as a 15-meter sprint time or a vertical jump height) to confirm that resistance training is producing genuine power gains rather than simply accumulating fatigue, and maintaining open communication with swimmers about shoulder, lower back, or hip discomfort, particularly given the additional joint stress that tools like paddles and heavy resistance parachutes can introduce.

Conclusion

Because the Individual Medley demands meaningful power production across four biomechanically distinct strokes, IM swimmers benefit disproportionately from a resistance training approach that is deliberately structured around each stroke's unique power demands, rather than a generic, one-size-fits-all strength program. By combining in-water resistance tools — parachutes, stretch cords, paddles, and isolated pull work — with targeted dryland strength training addressing upper body pulling power, rotational core strength, and lower body explosive power, coaches and swimmers can build the specific force-production capacity that underlies fast, sustainable performance across all four legs of the IM.

Structured thoughtfully across a training season, with careful attention to progression, specificity, and recovery, resistance training becomes one of the most valuable tools available for closing the gap between an IM swimmer's technical potential and their actual race performance — ensuring that when the technique is in place, the underlying power to execute it at full race speed, across all four strokes and even under significant fatigue, is there to match it.