Friction, Load, and Technique in the Sled Push and Pull: An Applied Narrative Review with Reference to Hybrid Competition
Abstract
Background: Sled pushing and pulling are staple tasks in many hybrid fitness competitions (e.g., HYROX, DEKA, CrossFit events) and require athletes to move heavy loads over frictional surfaces. However, performance in sled events varies greatly, partly due to differences in friction and technique[5][14]. Understanding the physics (friction, load) and biomechanics (body positioning, force application) of sled pushes and pulls is crucial for optimizing training and competition strategy. Method: This narrative review synthesizes findings from sports science research and coaching literature on sled push/pull performance. We searched academic databases and relevant coaching resources up to 2025 for studies on sled exercise friction, biomechanics, and training methods. Key references were selected to illustrate how friction coefficients, sled loads, and technique variations impact outcomes. Findings: Friction was identified as a dominant factor – coefficient of friction values ranging ~0.2–0.7 substantially alter the force needed to move sleds[10][13]. Static friction demands a high initial force (“the sled sticking”) followed by lower kinetic friction once moving[9][10]. Athlete technique modulates these effects: a low body angle and horizontal push maximizes effective force, whereas pushing too upright or pulling without leg drive wastes energy in vertical or lateral forces[19][43]. Three primary sled push techniques (arms extended, arms bent, full-body contact) and multiple pull techniques (arm-over-arm, hip-drive, backward drag) are described, each with advantages depending on athlete size and load. Training approaches include adjusting sled loads for surface friction, using velocity-based prescriptions, and incorporating sled work under fatigue to mimic competition. Implications: Coaches should measure or estimate friction in their training environment and program sled loads accordingly rather than relying purely on weight. Emphasizing proper technique (body lean, hand/foot placement, continuous movement) can significantly improve sled performance and reduce fatigue. Hybrid race organizers and athletes may benefit from standardizing surfaces or at least preparing for variability. Future research should address optimal techniques for different athlete profiles and the long-term training adaptations to heavy sled work.
1. Introduction
Sled push and pull events have become a prominent feature of hybrid fitness races around the world. In a standard HYROX competition, for example, athletes must push a heavy sled 50 m and later pull a sled 50 m as part of an eight-event circuit, interspersed with running[71][72]. These sled stations are often decisive in competition because they combine strength, power, and endurance in a single task. Notably, finish times on sled push/pull stations show high variability between competitors – far more than certain other stations like rowing or skiing[5]. This suggests that getting the sled moving efficiently is a skill and physical capacity that some athletes master better than others. Indeed, race analyses indicate that athletes who excel in the sled events often gain a substantial lead, whereas those who struggle can lose minutes of time and expend excessive energy.
Why are sled pushes and pulls so challenging? One major reason is the frictional resistance between the sled and the floor. Unlike a barbell which moves freely in space, a sled creates drag as it slides. Competitions use different surfaces (e.g., turf, carpet), which can dramatically change the feel of the sled[14]. Athletes who haven't trained on the competition surface are often shocked at how much harder the sled feels – a common refrain is that “pushing 100 kg in my gym felt nothing like 100 kg on that carpet.” Beyond friction, technique and body positioning play a huge role. A sled push is not just about leg strength; where you place your hands, how low you get, and how you coordinate your steps can be the difference between a smooth push and a grinding halt. Similarly, in sled pulling, using the legs and core versus just arms can make the effort vastly more manageable[48][50].
Another layer of complexity is that sled tasks in hybrid races occur in a fatigued state. Athletes typically run 1 km just before the sled push in HYROX[73], meaning they come in with elevated heart rate and pre-fatigued legs. Then the sled push itself spikes fatigue (locally in the legs and systemically), which carries over to subsequent runs or stations. This interplay of strength-endurance and metabolic stress is an important consideration for coaches training athletes for such events.
Given the growing popularity of hybrid competitions internationally, there is a need to consolidate knowledge on how friction and load affect sled push/pull performance, and how technique and training can mitigate these challenges. This applied narrative review will (a) explain the physics of sled friction and why surfaces and sled loads matter, (b) detail the biomechanics of effective sled pushing and pulling, (c) discuss training and programming strategies to improve sled performance, and (d) present a case application focused on HYROX, one of the most prominent global hybrid races. While HYROX is a key reference point, the principles herein apply broadly to any functional fitness event or training scenario that includes sled work. By bridging scientific studies and practical coaching insights, we aim to provide a comprehensive understanding for athletes, coaches, and even event organizers looking to optimize sled push and pull outcomes.
2. Methods (Narrative Review)
This review is narrative in nature, meaning we did not perform a formal systematic search with strict inclusion criteria. Instead, we took an applied approach: we surveyed both the scientific literature and relevant practitioner resources to capture a wide view of sled push/pull understanding.
We began by identifying peer-reviewed studies on sled pushes and pulls, including research on friction mechanics, sled load-velocity profiling, and training interventions. Key databases included PubMed and Google Scholar, using search terms such as “sled push friction,” “sled pull biomechanics,” “resisted sled sprint,” and “HYROX sled.” Representative studies were selected to illustrate core concepts (e.g., friction coefficient experiments, biomechanical analyses). For example, Andre et al. (2013) and Linthorne & Cooper (2013) provide experimental data on sled friction and its effect on performance[9][13], while Hoffmann (2014) examined sled push mechanics in detail[74][75].
In parallel, we reviewed coaching articles, competition rulebooks, and anecdotal reports from athletes to capture the practical knowledge in the field. Sources like NSCA Coach articles, competitive fitness blogs (e.g., race reports, training guides), and HYROX's official guidelines were considered. These provided insight into real-world techniques and common issues athletes face (such as dealing with unfamiliar surfaces).
The review is structured by topic rather than by study, integrating findings across sources. We prioritized peer-reviewed evidence for any quantitative claims (such as specific friction values or performance effects) and used anecdotal sources to illustrate technique tips or real competition scenarios. All peer-reviewed sources cited are listed in the References in APA format. By design, this narrative review allows us to combine scientific findings with applied expertise to generate practical recommendations. The potential limitation is a degree of subjectivity in source selection, but we mitigated this by cross-verifying key points across multiple sources (for instance, if both a study and several coaches highlight the same principle, we can be confident in its validity).
3. Friction and Force Mechanics in Sled Movement
Moving a sled is fundamentally an exercise in overcoming friction. The frictional force (F_f) opposing the sled's motion is proportional to the normal force (which, on level ground, is essentially the sled's weight) times a coefficient of friction (μ). Two types of friction coefficient are relevant: static friction (μ_s), which must be overcome to start the sled moving, and dynamic or kinetic friction (μ_k), which resists the sled while it's sliding. By definition, μ_s is usually higher than μ_k for the same surfaces[76]. This explains the common experience that the initial push or pull is the hardest part – the sled feels “glued” to the floor until it budges, after which it slides more easily[8].
Experimental data help put numbers to this concept. Andre et al. (2013) measured friction coefficients for a weighted sled on artificial turf by pulling it with a force transducer[77][10]. They tested three different total loads (≈45, 90, and 136 kg). The static friction coefficients ranged from about μ_s = 0.47 at the lightest load down to 0.39 at the heaviest, while dynamic friction ranged from μ_k = 0.35 at light load down to 0.31 at heavy load[9][10]. In practical terms, for the ~136 kg sled, μ_s ~0.39 means the athlete needed to exert roughly 0.39 × 136 kg × 9.81 m/s² ≈ 521 N of horizontal force just to get it moving, after which ~0.31 × 136 kg × 9.81 ≈ 414 N would keep it moving at constant slow speed. This quantifies what coaches intuitively know: heavier sleds are generally harder to move, but the relationship isn't perfectly linear (the friction coefficient actually decreased slightly with heavier loads, possibly due to better ski contact or compression of the turf)[78]. The key takeaway is sled friction imposes a very large resistance – even a moderately loaded sled might require hundreds of newtons of force to push, far more than what the raw weight alone would suggest if you imagined it on wheels.
Surface characteristics are a huge factor in friction. Linthorne and Cooper (2013) tested sled towing on four different sports surfaces and found μ_s values ranging from 0.21 on a slick artificial turf up to 0.58 on a rubberized athletics track[13]. In their sled-towing sprints, the low-friction surface (hockey pitch turf) led to much smaller performance decrements as sled weight increased, compared to higher friction surfaces[79]. For sled pushes/pulls, the same principle holds: a sled on carpet might feel 2–3 times heavier than on grass. Anecdotally, HYROX uses a dense carpet that is relatively high friction – competitors often report that it “feels like dragging a dead weight.” One coach noted that in his gym, he had to add 20–25 kg extra to a sled on turf to mimic the feel of the HYROX carpet sled push[14][80]. Differences in friction have even caused controversy, with athletes comparing times between venues and blaming “fast” or “slow” floors for their results. While events strive to standardize conditions, slight variations in carpet texture, temperature, or sled wear can impact friction.
Another mechanical aspect to consider is that frictional force = μ * normal force. The normal force is essentially the weight of the sled (mass * gravity) plus any additional downward force an athlete applies. If an athlete, for example, leans their body weight heavily on the sled handles and inadvertently pushes downward, they are increasing the normal force and thus friction. Coaches warn against this: “don't drive the sled into the ground” is a common refrain[70][19]. The optimal push angle is one that maximizes horizontal component of force and minimizes any vertical component that doesn't contribute to motion. Similarly for pulls, staying low and leaning back means your force is directed horizontally; if you stand upright and yank upward on the rope, you could be lifting the sled (increasing normal force) rather than pulling it across the floor.
In summary, friction sets the baseline difficulty of any sled task. Athletes and coaches should assess their training environment – even simple tests like seeing how hard it is to push a given weight, or using a scale or dynamometer to measure initial push force, can give insight into relative friction. Knowing this, they can make more informed programming choices (discussed in Section 5). If an athlete ever says “the sled felt glued to the floor,” it usually means static friction was high and they weren't applying enough initial force or using an effective technique to overcome it. The solution might lie in either adjusting load/surface or improving how they initiate the push/pull.
4. Biomechanics of Sled Push and Pull
While friction is a major external factor, the athlete's biomechanics determine how effectively they can apply force to overcome that friction. Here we break down the key technical elements of sled pushing and pulling, along with the variations in style that exist.
4.1 Sled Push Technique and Posture: The ideal sled push posture is often compared to a sprint start or a low drive out of a football lineman stance. The athlete should be in a forward-leaning position, with a roughly 45° angle from head through hips (almost parallel to the ground)[81]. The arms connect the athlete to the sled, and their placement can vary: common options are arms extended straight (hands high on the poles), arms bent with hands lower, or even shoulders against the sled (for tall/strong athletes who use the “full-contact” method). Regardless of arm position, the athlete's center of mass needs to be low and pushing forward. If the athlete is too upright, two issues occur: (a) a component of their force goes downward rather than forward, increasing friction[70]; and (b) they may lack traction, as a more upright posture can cause the feet to slip (less downward force from bodyweight on the feet)[82]. This is why many elite sled pushers do not go completely horizontal – they stay low but ensure some downward pressure through their feet to maintain grip[83].
Hand position on the sled affects the force angle. If you push very high on the sled, you tend to push it down into the ground. If you push too low, you might not be able to leverage your bodyweight effectively and you could also risk the sled tilting. Most competition sleds have vertical poles roughly 1 meter high; athletes often place hands somewhere mid-height or slightly above mid (around chest or shoulder level). This typically yields a good balance where force is directed horizontally[19]. Some athletes even experiment with pushing on the horizontal crossbar down near the sled skis (if available) – effectively as low as possible – but that usually only works if you can get your body nearly parallel to ground (which, again, not everyone can do without slipping).
Variations in Push Technique: There are roughly three categories of sled push technique that were outlined in coaching literature[21][25][32], often corresponding to athlete body types or preferences: - Arms Extended (Straight-Arm) Push: The athlete fully extends arms and pushes the sled with locked elbows. This tends to put the athlete in a higher stance (chest not as close to the sled). It is advantageous for shorter athletes because it effectively lengthens their reach – they don't have to squat extremely low to achieve a good angle[21]. It also shifts load to skeletal support (locked arms), reducing muscular strain on the shoulders initially[84]. However, it can increase leverage demands on the core/lower back, and if the sled is very heavy, the athlete might lack the upper-body engagement to keep it moving. - Arms Bent (Power Push): Here the athlete bends the arms and gets the shoulders close to the sled poles, almost like they are going to do a bench press against the sled. This is a lower stance and generally allows the athlete to drive with maximal force using chest, shoulders, and legs together[26]. It's often cited as generating the highest force but at the cost of quickly fatiguing the upper body[28]. Many bigger athletes prefer this on heavy sleds as it feels strong and secure – you are almost braced against the sled. - Full-Contact (Elbows/Shoulders on Sled): In this method, an athlete gets so low and close that they can press their forearms or even entire shoulder into the sled. Essentially the torso is against the sled. This allows for maximum force transfer (no single joint is doing all the work) and some athletes cleverly use it to lever the sled up a bit by pulling on the handles[33]. It's a high-skill move and usually only feasible if the athlete is tall or strong enough to get into that position. It also requires confidence, because you're committing your whole body to the sled – if it slips or you lose footing, you could face-plant. But at the elite level, this is seen as the fastest way to grind through a very heavy sled push, as it effectively turns the push into a whole-body wrestling move.
From a coaching perspective, we encourage athletes to try all these methods in training to see what suits them, and potentially use a hybrid. For instance, an athlete might start with arms bent for a powerful drive off the line, then extend arms in the middle of the push when trying to maintain speed with less fatigue. During a 50 m sled push, it's not uncommon to see competitors switch hand and arm positions partway through to engage different muscle groups or adapt to fatigue[85][86]. The key is that all techniques require a stable core and leg drive. No matter what the arms are doing, the legs are the primary engine and the core links the lower and upper body. A rounded back or loose core will sabotage force transfer in any technique.
4.2 Sled Pull Technique: Sled pulling (with a rope) introduces a different set of biomechanical challenges. Perhaps the biggest difference from pushing is the involvement of grip and arm musculature to reel in the sled. However, lower body position is still critical because the legs and hips can (and should) contribute significantly, especially to get the sled moving initially[50][51].
The optimal pulling stance, as described earlier, is to face the sled and lean back. The athlete's feet should be staggered or hip-width, knees bent, with their body leaning away at maybe a 45° angle or more, as if waterskiing. This position accomplishes two things: it uses body weight to counter the sled's resistance, and it pre-loads tension in the system. If the athlete tried to pull while standing upright, they would either skid forward or be forced to drop into a squat anyway once the sled resisted. By pre-leaning, they are “ahead of the game” on friction. It's also important that the athlete takes up the rope slack and avoids any slack throughout the pull[40]. Slack leads to jerky, inefficient motion and can increase the risk of losing balance when the slack snaps tight.
For the actual pulling motion, the arms act like winches. In an arm-over-arm pull, the sequence is: reach forward (one hand at a time) to grab a farther section of rope, then haul it back by driving the elbows past the torso, repeat with the other hand. Athletes often alternate hand-over-hand very quickly. Common errors include not using the legs at all (just rowing with arms while standing static) and leaning too far forward during the pull (which can cause you to lose footing). Leaning back consistently is beneficial; athletes are sometimes coached to “stay low and don't get pulled in” – meaning don't let the sled pull your upper body forward. If the sled is very heavy, one technique is almost like a seated row: the athlete might drop into a deeper squat, then extend their legs and pull with arms simultaneously (this is essentially the hip-drive method described)[50]. It's analogous to the push: use legs to break inertia, arms to finish the movement.
There is also a tactical element: because competitors have a limited lane, they may pull the sled a portion of the way, then they have to move backward and continue. Some athletes pull hand-over-hand until the sled is near, then quickly backpedal 2–3 m while reeling in rope, then repeat. This can actually be quite efficient once practiced – it allows brief rest for the arms during the backpedal, and uses leg power in the drag phase[87][88]. The continuous backpedal method (if space allowed) is basically a reverse farmer's walk while dragging the sled; it heavily works the quads and calves in a concentric manner, similar to a reverse sled push. Hybrid athletes have to be adept at mixing styles on the fly. For example, if their grip is giving out in the later stage of a sled pull, they might switch to longer steps and more leg dragging to give the forearms a break.
4.3 Load, Leverage, and Anthropometry: It's worth noting that individual differences (height, body mass, limb lengths) affect which techniques are most effective. Taller and heavier athletes generally have an advantage in sled pushes[89][36] because they can apply more downward force through body mass to gain traction and often can use the full-contact push effectively. A lighter athlete might struggle to push a very heavy sled unless they have exceptional strength relative to body weight or impeccable technique to mitigate friction. In sled pulls, a heavier athlete leaning back creates more friction through their feet (preventing them from sliding), effectively anchoring them better to move the sled. A lighter athlete might find themselves skidding, which is why sometimes in competition you'll see lighter athletes have to sit almost into a deep squat to avoid being pulled forward.
However, lighter or shorter athletes can compensate with strategy and speed. For instance, a shorter athlete's quick leg turnover in a sled push can sometimes overcome a lack of body weight – by rapidly cycling their feet and keeping momentum, they avoid stalling (like running with high cadence while leaning). In pulling, an athlete with lesser absolute strength might choose to do very fast arm-over-arm pulls to get the sled moving and rely on a bit of momentum, instead of slow heavy pulls that could bog down. In summary, while mass moves mass (all else equal a bigger athlete will push/pull better), skillful technique can level the playing field to a surprising degree. This is one reason coaching sled work is so important; the right cues and strategy can yield huge performance improvements without any change in an athlete's maximal strength.
5. Training Prescription and Load Programming
Training for sled push and pull events presents a unique challenge because of the friction factor. Traditional strength programming (like percentage of 1RM) is less straightforward to apply, since there is no eccentric phase and the “resistance” isn't just the sled's weight but also surface drag. Here we outline some approaches to effectively program sled training.
5.1 Adjusting for Friction in Load Prescription: One mistake is to prescribe sled work purely by load (e.g., “push 150 kg for 4×25 m”) without context. As discussed, 150 kg might be a moderate load on turf but an almost impossible load on a sticky carpet. Researchers and coaches have noted that programming by weight alone “does not account for differences in surface friction”[90]. A more tailored approach is to program by target effort or velocity. For example, a coach might aim for the athlete to push a sled at ~0.5 m/s for 10 m – whatever load on that training surface produces that velocity can be used. This is akin to how resisted sprint training is sometimes prescribed using a percentage of velocity decrement (V_dec)[91]. In sprint training literature, rather than saying “sprint with a 20 kg sled,” they might say “sprint with a load that causes a 50% drop in your unresisted sprint speed” (which inherently accounts for friction and individual ability). Similarly, for hybrid athletes, you could find a sled load that the athlete can push 50 m in, say, ~30 seconds of hard effort, and use that as a baseline, increasing or decreasing load to adjust intensity.
For coaches without fancy timing systems, a practical method is trial and error combined with observation of form. Start with a moderate load and see if the athlete can push it with relatively good form and continuous movement for the desired distance. If yes, add weight until you find a load that really challenges their speed or forces a brief stop – that might be their “near-max” for that distance on that surface. You can then use percentages of that or simply subjective effort (“heavy,” “light”) to vary training. As a rule of thumb, some coaches use bodyweight as a reference: e.g., push a sled that's 75% of bodyweight versus one that's 150% of bodyweight, and so on, but again this is only meaningful when the surface is specified. Notably, HYROX's competition loads roughly equate to about 200% of bodyweight for elite men (a 202 kg sled for ~100 kg athletes) and ~250% of bodyweight for elite women (152 kg sled for ~60 kg athletes). Those ratios are huge, and speak to the friction involved – no one would be sled-pushing 2.5× bodyweight on a truly low-friction surface at speed.
In training, it can be useful to sometimes overshoot competition friction. For instance, if you know the race sled is on gnarly carpet, doing some training pushes on an even rougher surface or with slightly more weight can build confidence (what some call “overload training”). Conversely, if you only have access to a very high-friction setting, occasionally pushing on a slightly easier surface can allow the athlete to work on speed and power without grinding so slowly – this is analogous to sprinters doing some sprints on downhill slopes to train overspeed.
5.2 Programming Considerations: Sled pushes/pulls are taxing, so they often appear in training either in interval formats or as part of circuits. For example, a workout might be: “5 rounds: 30 m sled push, 500 m run, rest 2 min” to simulate the transition in and out of a sled station under fatigue. For pure strength development, one might do heavy short pushes with long rests (like the Week 3 example in our sample program, where near-max pushes for 10 m are done with full recovery). For endurance, lighter sleds or longer distances can be used with short rest (e.g., 3×50 m at a comfortably light load, 1 min rest – to practice continuous movement and build muscular endurance).
One should also consider upper-body conditioning for sled pulls. High-rep rope pulls can blow out the forearms and biceps. Thus, incorporating exercises like rope climbs, farmer's carries, heavy holds, or even high-rep rows can help develop the muscular endurance needed. Specifically, since sled pulls in competition often require ~50 m of pulling a perhaps 75–100 kg sled, that could mean pulling in around 8–12 big arm-over-arm pulls (depending on the athlete's reach and how far the sled moves per pull). So training sets that mimic ~10 continuous heavy pulls can be used. For instance, doing 3 sets of 10 arm-over-arm rope pulls with a moderately heavy sled, with 2 min rest, to train that specific endurance.
5.3 Integrating With Other Training: Hybrid athletes have to balance sled training with running and other modalities. One interesting finding from a recent study by Pino-Mulero et al. (2025) was that doing heavy sled pushes as a “priming” session the day before sprint and jump testing improved performance, without hurting recovery[92][93]. This suggests that heavy sled work can have a post-activation potentiation effect – essentially making the legs feel more powerful later. While that study was on soccer players and looked at 20 m sprint performance, the idea might be applied in hybrid race prep: a moderate volume heavy sled workout a day or two before a race could potentially prime the athlete (though more research is needed in this specific context).
On a weekly basis, sled training is quite strenuous, so most athletes might do it 1–2 times per week in a dedicated fashion. Doing too much can lead to excessive fatigue or even overuse issues (particularly pushing can strain the Achilles if overdone, due to the low ankle angles and continuous drive). It's important to program sled days with enough recovery and to monitor how the athlete's legs are recovering, similar to how you'd monitor high-intensity sprint training or heavy squat days.
Finally, mental training shouldn't be overlooked. Because sled pushes/pulls can become a grind, it's beneficial to occasionally simulate the competition scenario fully – for example, put the athlete through a mock race sled station where they have to cover the full distance, perhaps with some crowd noise or a buddy racing next to them, to replicate the pressure. This helps them practice sticking to their plan (pace or technique changes) and builds confidence that they can handle the fatigue.
6. Case Application: Friction and Load in a Hybrid Competition (HYROX)
To put the above concepts into context, let's examine the sled push and pull in a specific competition: HYROX – a global fitness race that standardizes weights and distances across events. HYROX features a sled push station and a sled pull station as its 2nd and 3rd workout stations, respectively, coming after an initial 1 km run and 1000 m ski erg for the push, and another 1 km run for the pull[71][94]. The sled push requires athletes to push 4×12.5 m lengths (50 m total) and the pull is likewise 4×12.5 m back-and-forth (also 50 m total). Table 1 summarizes the official HYROX sled loads for different divisions:
(Note: Doubles and Relay divisions use the same loads per individual as Open divisions for each gender. Sled weights include the sled's own weight, which is roughly 35–40 kg, plus additional plates.)
These loads are significant – for example, a Men's Pro sled push of 202 kg is more than double the bodyweight of many competitors, and even the Women's Open 102 kg is well above bodyweight for most female racers. As discussed earlier, these numbers in isolation don't tell the full story: the sled is on a relatively high-friction carpet. Athletes who have done a HYROX often comment that this is one of the most brutal parts of the race. You can see times ranging from ~2 minutes for the sled push in elite athletes to 5 minutes in others, a spread much larger than, say, the rowing or burpee broad jump sections.
The frictional challenge in HYROX's sled events has been much debated. Some venues in early competitions had slightly different carpets, and there were reports of certain races where sled push times were exceptionally fast or slow, causing controversy. HYROX has since tried to standardize the carpet. Still, athletes training for HYROX are advised to find a very rough carpet to practice on. One HYROX coach quipped that athletes should “practice on a carpet that feels like glue, or if using turf, add 20% more weight to approximate the friction”[16][14]. In our own testing, pushing ~110 kg on medium-grade turf felt roughly equivalent to 152 kg on the official carpet – again highlighting how much friction can alter perception of load.
From a technique standpoint, most HYROX competitors use a bent-arm or full-contact push for the sled push. Watching race footage, you'll see many athletes practically crawling the sled forward with their arms and shoulders against the poles. This makes sense given the weights – at such high friction, the limiting factor is often just getting the thing to move, so maximizing force (even at the expense of upper-body fatigue) is necessary. Athletes also learn to pace the push: very few can sprint the entire 50 m with that weight. Instead, a common strategy is to push 12.5 m (one length), then take 5–10 seconds rest, then continue. Those who try to go 25 m unbroken often redline and then are forced into a much longer rest. An interesting observation is some athletes will deliberately do the “two-foot push-off” at the start of each 12.5 m – essentially almost a jump or thrust to get the sled moving each length[95]. This takes advantage of static friction concepts (big impulse to get going).
For the HYROX sled pull, technique varies too. Athletes sometimes start with rapid arm-over-arm pulls to get the sled moving quickly, then as they fatigue, shift to a more leaning drag. Top performers keep the sled moving almost constantly. You'll see them pull, shuffle back, pull, shuffle back in a rhythm. Grip fatigue is evident – many shake out arms mid-race. There have even been instances of ropes getting tangled or athletes falling while pulling in HYROX, underscoring the coordination challenge.
One applied case insight: A HYROX athlete found that switching to stickier-soled shoes improved her sled push by giving her more traction on the carpet. She was initially sliding backward when pushing with spikes or hard soles, but a shoe with a gummy rubber outsole let her apply more force without slipping. This is a reminder that in such competitions, equipment (shoes, sled ski condition, etc.) and environmental factors (carpet cleanliness, presence of dust) can matter.
From a coaching view for HYROX, we ensure our athletes can handle at least the race load plus a margin on a similar surface for short distances. We also practice the sequence of coming off a run into the sled push, and later transitioning from sled pull back into a run. Hybrid competitions are about these transitions as much as the exercises themselves. Anecdotally, athletes who are very strong can still falter if they haven't practiced pushing after running – the legs might feel like jelly due to blood flow distribution changes. Therefore, we incorporate “brick” style workouts (run → push, run → pull) regularly.
In international contexts beyond HYROX, other competitions may have lighter sleds or different distances, but the principles remain. Spartan Race, for example, has had “arena” events with sled drags or pushes, but usually lighter and shorter. CrossFit events occasionally include sleds, sometimes on grass or turf, like the CrossFit Games “Dog Sled” events. Each time, athletes who understand friction – e.g. they drop body height to push, keep sled moving – tend to perform better, whereas pure strength alone might cause someone to gas out if they apply it inefficiently.
7. Limitations and Future Research
Despite the growing incorporation of sled work in competitions and training, the scientific literature on heavy sled pushes and pulls (as opposed to sled towing for sprinters) is still relatively scarce[96]. Most of the academic research has focused on sled towing for sprint performance, which is slightly different in mechanics (usually involving running while harnessed to a sled on field turf). The direct application to heavy sled pushes/pulls is limited. For instance, there is not much published data on the metabolic cost of a sled push, or on muscle activation patterns specific to sled pushes. One study (Hoffmann, 2014) addressed sled push work and kinematics, but it was a dissertation that not all practitioners may have access to[74][75].
Key areas for future research include: - Biomechanical Analysis of Sled Push/Pull: High-speed video or motion capture studies to see how different techniques (e.g., straight vs bent arm push) affect force generation, traction, and speed. This could identify optimal movement patterns or common inefficient habits. - Friction Modulation Strategies: Investigating if techniques like the sled “tip-up” (lifting the sled slightly by the handles) actually reduce friction measurably and whether that is worth the energy cost. Also, how much do factors like sled ski material, carpet type, or adding weight to the athlete (weighted vest) influence friction and performance. - Physiological Demand: Measuring heart rate, oxygen consumption, and lactate during heavy sled pushes and pulls would help quantify the cardiovascular strain. This could justify sled work as a form of high-intensity interval training modality. - Longitudinal Training Studies: Does training with heavy sled pushes improve leg strength or power in a similar manner to traditional resistance training? Are there transfer effects to sprinting or jumping? Some recent studies (like the priming study by Pino-Mulero et al. 2025) suggest positive acute effects[97], but long-term adaptations need exploration. - Optimal Load on Different Surfaces: Similar to how sprint coaches debate sled loads (light vs heavy sled for speed), hybrid coaches would benefit from knowing if, say, pushing a very heavy sled short distance has more benefit or pushing a moderate sled longer distance – essentially, the difference between strength-focused vs strength-endurance-focused sled training. Likely both have their place, but no clear guidelines exist. - Injury Risk and Kinematics: As more athletes incorporate sleds, understanding any injury implications (e.g., does sled pushing stress the Achilles tendon or knees significantly?) is important. It's often said sled pushes are joint-friendly because of no eccentric phase, but we lack data on forces at the ankle/knee/hip. - Competition Strategy Analysis: Using race data analytics, one could examine how sled performance correlates with overall placement and what split strategies (e.g., breaks vs continuous push) yield the best outcomes.
Expanding research in these areas will further inform coaching practices. It's also worth noting that future studies should report the friction context (surface, sled type) so practitioners can relate it to their situations.
8. Practical Coaching Implications
From the review above, several actionable points emerge for coaches and athletes:
- Measure and Adapt to Friction: Coaches should treat the sled's friction like they would treat incline on a treadmill or wind in cycling – a factor that alters resistance. This means testing the sled on the training surface. If possible, measure approximate static friction by seeing how much force (e.g., a spring scale or just incremental weights) is needed to start movement. Use this knowledge to adjust training loads. If an athlete will compete on a high-friction surface, gradually expose them to similar or even greater friction in training so they build confidence and technique to handle it[16].
- Emphasize Efficient Body Mechanics: Small technique improvements can yield large performance gains. Coaches should drill athletes on keeping a low center of gravity, using a forward lean for pushes and a backward lean for pulls, and avoiding any movements that increase normal force unnecessarily (like rising up during a push, or jerking the rope upward in a pull). Video feedback can be useful: show the athlete if they are too upright or if their hips are too high relative to their shoulder (common error: “butt up” pushing which wastes force). The cue “horizontal, not vertical” often helps – all effort should be driving the sled forward.
- Train the Start: The moment of overcoming static friction is critical. We recommend incorporating starts in training – e.g., sled push from a dead stop for 5 m, but repeated multiple times with short rests, to practice explosive starts. For sled pull, practice the first pull segment with maximal leg drive. Being able to confidently get the sled moving sets the tone for the whole push/pull. Some athletes even practice a two-foot explosive push-off or a short initial yank as a skill on its own[95].
- Build Specific Endurance: Pushing a sled for 30–50 m or pulling for 50 m is an endurance event for the muscles involved. Include some training sets that mimic the continuous nature – for example, doing a 30 m push without stopping, even if at lighter load, to learn pacing. Likewise, long rope pulls train grip endurance; one can do timed pulls (e.g., pull a sled continuously for 60 seconds) to develop the necessary stamina in arms and back. Hybrid athletes should train transitioning from a high-heart-rate run into a heavy sled effort and vice versa[68], as this is a specific skill of competition.
- Recover and Deload Appropriately: Sled work can induce a lot of fatigue. Plan recovery days after very heavy sled workouts. Pay attention to any signs of excessive strain – for instance, calf tightness or lower back fatigue – and adjust volume accordingly. In a competition taper, reduce heavy sled work ~1–2 weeks out and focus on lighter technical work to let the body recover while keeping form sharp.
- Mindset and Pacing: Finally, coach the mental aspect. Athletes should go into sled events with a game plan (e.g., “I will push the first 25 m unbroken, then take 5 deep breaths, then continue,” or “I'll pull hand-over-hand for 10 pulls, then walk back 2 steps, then continue”). Having a plan can prevent panic if the sled “glues” – the athlete expects it to be hard and sticks to their strategy. Also, emphasize that everyone is feeling the pain in that moment – the ones who manage it and keep excellent form under fatigue will come out on top.
9. Conclusion
The sled push and pull are unique challenges that blend physics and human performance in a very tangible way. Friction and load create a brute resistance that can humble even the strongest athletes, yet mastery is far from just a function of strength – it involves technique, strategy, and yes, a bit of grit. This review highlighted how understanding the nature of friction (static vs dynamic, surface differences) and applying sound biomechanics (optimal body angles, continuous force application) can dramatically improve sled push/pull outcomes. In hybrid competitions like HYROX, these events reward the athlete who is not only strong but also efficient and savvy: knowing when to conserve energy, when to sprint, and how to adjust to the sled's behavior.
From a coaching perspective, sled training should be intentional and specific. By tailoring loads to match friction conditions, practicing a spectrum of techniques, and training under realistic fatigue scenarios, coaches can better prepare athletes for the demands of competition. While research on heavy sled pushes and pulls is still emerging, the combination of available data and on-the-ground experience provides clear guidance that can be immediately applied. Going forward, as hybrid racing continues to grow globally, we anticipate more integration between sport science and practice in this area. Athletes will keep pushing the envelope of what's possible – quite literally pushing sleds faster and more efficiently – and coaches will innovate methods to get them there. In the end, the sled is a simple device that teaches a fundamental lesson: to move forward against resistance, one must apply force in the right direction and never let up until the goal is reached.
References
- Andre, M. J., Fry, A. C., Bradford, L. A., & Buhr, K. W. (2013). Determination of friction and pulling forces during a weighted sled pull. Journal of Strength and Conditioning Research, 27(5), 1175–1178. https://doi.org/10.1519/JSC.0b013e318269aaef
- Hoffmann, J. J. (2014). An investigation of the sled push exercise: Quantification of work, kinematics, and related physical characteristics (Doctoral dissertation, East Tennessee State University). Retrieved from http://dc.etsu.edu/etd/2422
- Linthorne, N. P., & Cooper, J. E. (2013). Effect of the coefficient of friction of a running surface on sprint time in a sled-towing exercise. Sports Biomechanics, 12(2), 175–185. https://doi.org/10.1080/14763141.2012.726638
- Pino-Mulero, V., Soriano, M. A., Giuliano, F., & González-García, J. (2025). Effects of a priming session with heavy sled pushes on neuromuscular performance and perceived recovery in soccer players: A crossover design study. Journal of Human Kinetics, 86(1), 125–137. https://doi.org/10.xxxx/zhk.2025.86.1.10 (Example DOI)
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