After a squad swim session a couple of weeks back, star triathlete Susanne asked me why strides and hill sprints (examples here) are integral to my run training, but their swim equivalents are less common in my plans. Great question and well worth a deep dive.

My Logic for Run Training

1. Ground Reaction Forces (GRFs):

   • Running is heavily influenced by GRFs, as the runner interacts with a solid and consistent medium (the ground). The ability to generate and utilize force against the ground efficiently is a key determinant of speed.

   • Research highlights that strides and sprints improve muscle recruitment, motor unit synchronization, and firing frequency, all of which are critical for improving running economy and peak force output. The controlled environment (ground) ensures predictable resistance, allowing the nervous system to refine force application patterns.

2. Economy Through Neuromuscular Training:

   • Strides, characterized by short bouts of controlled speed with perfect form, improve running economy by fine-tuning biomechanics and minimizing energy wastage which translates even to slower paced running.

   • Hill sprints further enhance force production, particularly in the posterior chain (glutes, hamstrings, calves), crucial for efficient running. They also train elastic recoil in tendons, contributing to the spring-like efficiency of skilled runners.

3. Injury Prevention:

   • These activities not only enhance performance but also build strength and resilience in muscles and tendons, reducing injury risks associated with distance running.

Why Similar Logic Does Not Fully Apply to Swim Training

Swimming differs fundamentally from running due to the absence of a stable medium (ground) and the dominance of skill in propulsion. The ground reaction forces in running allow for more predictable propulsion versus the complex, multi-directional forces in swimming.

1. Fluid Dynamics and Propulsion:

   • Unlike running, where force application directly results in forward motion, swimming requires mastery of fluid dynamics. Applying more force in the water without proper technique often leads to inefficiencies, such as slipping or turbulence, rather than increased speed.

   • The principle of "holding water" involves maintaining a stable hand position to create effective propulsion. Studies show that the ability to apply force effectively in swimming is heavily dependent on technical skill rather than raw power.

2. Skill-Dependent Nature of Force Application:

   • In swimming, propulsion is generated by the coordinated movements of the arms, legs, and core. Poorly timed or imprecise movements can diminish the benefits of additional force.

   • This reliance on skill makes it more challenging for non-expert swimmers to translate increased effort into improved speed. Short, high-intensity sprints in swimming could reinforce poor habits if not performed with proper technique.

3. The Role of the Swim Kick:

   • The kick is a critical component of sprint swimming but has a reduced role in long-distance freestyle. Research shows that in events longer than 400m, the kick primarily aids body balance and reduces drag rather than providing significant propulsion. This underscores the importance of training the kick differently for distance swimming.

   • Emphasizing sprint-like kicking in training may develop muscular endurance in the legs but does not necessarily improve overall efficiency or race-specific performance in longer events (or swimrun).

Potential Confusion

It’s just a fact that competitive pool swimming is sprint based. The vast majority of events at a swim meet are less than 2 minutes long. It is therefore not surprising that the dominant training philosophies are sprint rather than distance focused. For example Ultra Short Race Pace Training (USRPT) focuses on replicating race conditions through short, high-intensity intervals performed at race pace. On the surface this may appear similar to the run speed stimuli but the training medium and its application are different. After all, if your race pace is the same as your max pace it makes a difference to specificity in training.

1. Race-Pace Specificity: Swimmers train at or near their target race speed, enhancing physiological and neurological adaptations specific to their competitive events.

2. High Intensity, Low Volume: Sessions consist of short, intense efforts interspersed with short rest periods, prioritizing quality over quantity.

3. Feedback and Adaptation: Swimmers receive immediate feedback during sets, allowing them to focus on maintaining proper technique under fatigue.

One thing I like in USRPT is the “stopping rule” swimmers typically stop after:

• Two consecutive missed intervals, or

• Three total missed intervals within the set.

This rule provides a balance between challenging the swimmer and maintaining the integrity of the training session. The rationale for stopping when the interval pace cannot be maintained is to preserve the quality and purpose of the training session. 

For distance swimmers or swimrunners even if our race-pace is slower I think this is good practice. Let’s say your target race-pace is 1:30/100m and you set yourself a series of 100m intervals with 15s rest at this pace. If after a few intervals you fail to hit the pace,  by continuing your stroke mechanics will degrade due to fatigue, leading to poor form and reinforcing inefficiency. It is better to stop (or use tools e.g. fins, pull-buoy etc.) rather than cementing sub-optimal technique for the remaining intervals.

By avoiding subpar repetitions, swimmers ensure they are developing target-pace-specific skills, reinforcing proper mechanics, and preventing overtraining or injury. Let’s take an analogy with another high skill sport - golf. During a visit to the driving range if my drives were slicing, I wouldn’t just continue to flub the whole bucket of balls way out right.

Training Nervous System Responses in Swimming

As many of my squad are non-expert swimmers with varying levels of inefficiency in their stroke, and/or difficulty maintaining form under fatigue; I use paddles and pull buoys to complement full stroke swimming in most of my sessions. Interestingly I have found pull/paddle swimming to be beneficial across all swim abilities and based on this thought experiment I plan to introduce more short sprints with paddles:

1. Improved Water Feel and Propulsion Mechanics:

   • Paddles increase the surface area of the hand, enhancing the swimmer’s ability to feel and "hold" the water. This feedback improves the connection between effort and propulsion, helping the swimmer refine their stroke mechanics.

   • The resistance provided by paddles also helps build strength in the pulling muscles (latissimus dorsi, biceps, and forearm muscles) without compromising technique.

2. Reduced Technical Demand at Higher Intensity:

   • Short sprints with paddles allow swimmers to train at high intensities while maintaining proper form, as the added resistance encourages deliberate and efficient movements.

3. Nervous System Adaptation with Technique Emphasis:

   • High-intensity efforts with paddles can stimulate nervous system adaptations similar to strides in running. However, the key difference is the emphasis on technical precision rather than brute force.

   • A study published in Frontiers in Physiology (2023) reported that hand paddles significantly altered front crawl kinematics, leading to adjustments in stroke mechanics that can improve propulsion efficiency. 

Practical Adaptations

While strides and hill sprints are indispensable for runners, swim training demands a nuanced approach that prioritizes skill development alongside neuromuscular adaptation, so putting this into practice:

1. Integrate Paddle Sprints with Technical Feedback:

   • Combine short sprints (10–15 meters) with hand paddles and post-effort video analysis or coach feedback to ensure proper stroke mechanics are maintained.

2. Progress to Resistance Training:

   • Advanced swimmers can transition to resistance-based training, such as pulling a drag parachute or swimming with the Fike Mortar, which mimic the force application benefits of hill sprints while emphasizing technical control.

3. Drills for Specific Neuromuscular Patterns:

   • Use drills that isolate stroke components, such as sculling (to improve water feel) or single-arm freestyle (to refine body rotation and alignment), to target nervous system responses in a controlled, skill-focused manner.

4. Periodize Sprint Training:

   • Incorporate short high-intensity swim sprints in specific training phases, ensuring that technique is consistently prioritized over sheer force application.

5. Balance with Overall Objectives:

   • Nearly all the swimmers I train with are multisport athletes. Therefore we must pursue synergies across disciplines. In my case swimming acts as aerobic cross training for my running and this support role is key. Optimizing my swim training at the expense of this base-aerobic contribution would be a negative tradeoff

Conclusion and Key Takeaways

Strides and hill sprints in running and tailored neuromuscular swim training offer powerful ways to improve performance across both disciplines. Here’s a summary of the main points:

• Running:

  • Strides and hill sprints enhance running economy by improving muscle recruitment, motor unit synchronization, and elastic recoil in tendons.

  • These tools build strength and resilience, reducing injury risks while improving speed and efficiency.

  • The consistent medium of ground allows for predictable force application, making strides and sprints an ideal way to train the neuromuscular system.

• Swimming:

  • Swimming relies heavily on skill; applying more force without proper technique often reduces efficiency.

  • Tools like paddles improve water feel and propulsion mechanics, helping swimmers refine their technique while building strength.

  • Short, controlled sprint efforts with a focus on maintaining proper form are crucial for optimizing swim-specific neuromuscular responses.

• General Training Principles:

  • Race-pace-specific training, as seen in USRPT, highlights the importance of maintaining quality over quantity, stopping when form degrades to avoid reinforcing poor habits.

  • Multisport athletes must balance swim and run training, ensuring swimming supports overall aerobic conditioning without compromising the performance in other discipline(s).

For a multisport athlete, it’s important to remember that you are not training swimming and running in isolation. Both the training and the racing must be synergistic, with each discipline complementing the other. A well-balanced program ensures that swimming supports overall aerobic conditioning without compromising your ability to excel in running (or biking), creating harmony between the demands of each sport for optimal performance.