Running Technique Optimization: Cadence, Ground Contact Time, and Vertical Oscillation — The 180 Myth and Interpreting Watch Data

Let me start with a picture. One winter two years ago, a student named A-Kai came to me with a brand-new high-end running watch, and his first words were: “Coach, my cadence is only 172. Is my running form broken? Everyone online says it should be 180.” He turned his watch screen toward me, full of data—cadence, ground contact time, vertical oscillation, running power, ground contact balance, and something called a “running efficiency index.” He was anxious because every number next to it was flagged yellow or red by the app, as if every part of him was a flaw.

I’ve coached triathlon and road runners for 15 years, from first-timers who cried at their first 51.5 distance to veterans who earned Kona slots. Over the years, I’ve seen too many people like A-Kai: not defeated by their own bodies, but terrified by the numbers on their watches. In this article, I want to talk to you properly about the three most misunderstood—and most often wrongly tinkered with—running technique metrics: cadence, ground contact time, and vertical oscillation. I’ll break down the most widespread myth of “180 cadence,” teach you how to read the running power data your watch gives you, and finally—and this is the most important part—tell you where the real risks of technique modification lie, and how a responsible coach would help you manage those risks.

Let me give you the conclusion first: These three numbers are “outcomes,” not “targets.” Treating outcomes as targets to chase hard is often the beginning of injury. Over these 15 years, I’ve seen too many passionate and hardworking runners who, by mistaking the dashboard for the steering wheel, trained themselves into injury, regression, or even a loss of passion for running. If this article can help you avoid even part of that detour, it’s worth it.

Why Is Everyone Talking About Cadence, Ground Contact Time, and Vertical Oscillation?

Before we get into the myths, we need to understand what these three metrics actually describe. They’re really answering the same question from different angles: Where is the energy of each step going?

Cadence: How Many Steps You Take Per Minute

Cadence is the total number of steps per minute (both feet combined), measured in spm (steps per minute). A typical recreational runner falls between 155 and 175, while elite runners often exceed 180 at race pace. A higher cadence usually means your foot lands closer to directly beneath your center of mass, reducing the “braking effect”—that is, the foot reaching too far forward, landing ahead of the center of mass, and producing a reaction force that pulls you backward.

Ground Contact Time (GCT): How Long Your Foot Stays on the Ground

Ground contact time is the number of milliseconds each foot is in contact with the ground per step. Most runners are around 200 to 300 milliseconds, while elite runners can push it down to 150 to 200 milliseconds in competition. Research does show a significant correlation between ground contact time and running economy (how much oxygen you consume at the same pace)—shorter ground contact time usually means better running economy. But here’s a key trap, which I’ll spend a whole section on: short doesn’t mean that “deliberately forcing it shorter” will make it better.

Vertical Oscillation (VO): How Much You Bounce Up and Down

Vertical oscillation is the amplitude of your center of mass moving up and down in each step, measured in centimeters. Most runners are around 6 to 11 centimeters. The logic is intuitive: the energy you put into jumping upward doesn’t directly contribute to moving forward—the higher you jump, the more you waste. Runners with good economy typically have smaller vertical oscillation, longer stride length, smaller speed changes at ground contact, and lower peak ground reaction forces.

Some running watches also divide vertical oscillation by stride length to calculate the “Vertical Ratio.” This ratio is more meaningful than looking at amplitude alone—because taller runners with longer strides naturally have larger absolute amplitudes, so using the ratio is fairer.

Why “Elasticity” Matters More Than “Force”—A Little Exercise Science Foundation

Before going further, I want to build a core concept that will run through this entire article: Good running technique is essentially about efficiently “recycling energy,” not desperately “producing energy.”

The human lower limb, especially the Achilles tendon and the arch of the foot, is a set of exquisitely tuned springs. When your foot lands and your center of mass lowers, these tendons and fascia are stretched, storing elastic potential energy; then, at the instant you push off the ground, that energy is released to help propel you forward. In exercise science, this “lengthen-shorten” process is called the Stretch-Shortening Cycle (SSC). A runner with good economy gets a large portion of their propulsion “for free” from this spring, rather than by muscling each step out.

This explains why metrics like ground contact time and vertical oscillation correlate with running economy. Too long a ground contact time means your spring has “deflated”—energy is stored but doesn’t spring back in time, dissipating as heat and deformation. Too large a vertical oscillation means you’re spending too much energy “jumping up” instead of “moving forward.” Conversely, a runner with good elasticity and crisp ground contact looks light, springy, “bouncing” across the ground rather than “stomping.”

Once you understand this, you’ll see why I keep emphasizing “train elasticity and strength, don’t deliberately chase numbers”—because those pretty numbers are byproducts of a good spring. Nurture the spring, and the numbers will naturally look good; bypass the spring and force the numbers, and what you get instead is stiffness and injury.

Where Did “180 Cadence” Actually Come From?—Breaking Down the Biggest Myth

This number is practically a “golden rule” every runner has heard, but its origin is far more casual than you might think.

The Telephone Game of a 1984 Olympic Observation

The “180 cadence” can be traced back to renowned coach Jack Daniels’ observations of elite runners at the 1984 Los Angeles Olympics—he found that most top athletes had cadences above 180 spm during races. Note the three premises in that statement: elite runners, race pace, above 180. As it spread, it morphed into “everyone, at any pace, should be exactly 180.” That’s a massive logical leap.

I often tell my students: this is like watching an F1 driver hit 300 km/h on a straightaway, then going home and deciding you should also drive 300 in the city—that’s not learning from elites, that’s asking for trouble.

What Does Research Say? Elite Cadence Spreads Are Astonishingly Wide

If you actually measure elite runners, you’ll find individual differences in cadence so large that a “single number” becomes almost laughable. One analysis of 100 km World Championship runners showed that these world-class ultramarathoners had individual cadences ranging from 155 to 203 spm—a gap of 48 steps (source at the end). These are all excellent runners, yet their “optimal cadence” varies wildly.

Additionally, research published in PLOS ONE indicates that many runners’ most economical cadence actually falls in the 165 to 175 spm range, where heart rate and oxygen consumption are lowest (source at the end). The research also found a fascinating phenomenon: runners subconsciously choose the cadence that is most energy-efficient for them. In other words, your body’s autopilot system likely understands you better than the red warnings on your watch.

Cadence Changes with Speed—This Is the Key Point

This is what most people overlook: For the same person, the optimal cadence differs at different paces. On an easy recovery run at 6:30/km, your cadence might be 165; pushing a half marathon at 4:30/km, it naturally rises to 182. That’s not a form problem—that’s just how human biomechanics normally works.

Most runners only naturally approach 180 at around 4:20/km or faster. So if you’re on a recovery run at 5:30/km and force your cadence to 180, it will feel very “choppy” and unnatural, and actually cost you more energy.

Scenario (typical amateur runner)	Typical Pace	Natural Cadence Range	Consequences of Forcing 180
Easy recovery run	6:00–6:30/km	160–170 spm	Stride too short, choppy movement, more tiring
Aerobic base run	5:15–5:45/km	168–176 spm	Slightly unnatural but acceptable
Tempo / half marathon pace	4:40–5:00/km	176–184 spm	Close to natural, usually no need to adjust
Intervals / 5K pace	4:00–4:30/km	182–190 spm	Already there naturally, no need to force

Once you understand this table, you’ll see: 180 is not a target; it’s just the natural result for “some people at some speeds.” Treating it as a hard metric across all paces is getting the cause and effect backwards.

Reading Your Running Watch: How to Interpret Running Power and Dynamics Data

Modern high-end running watches (Garmin, COROS, Polar, etc.) give you a ton of “running dynamics” data, and even “running power” (in watts). Students most often ask whether these numbers are trustworthy and how to use them. I have three principles.

Principle One: Look at Trends, Not Absolute Values

Running watches estimate running power and dynamics mostly through wrist, chest strap, or shoe pod sensors combined with algorithms. Numbers from different brands and algorithms can’t be compared to each other, and even the same watch can shift with a firmware update. So absolute numbers don’t mean much; comparing yourself to yourself over the long-term trend is what matters.

For example: don’t worry about “is my running power of 260 watts high or low?” Instead ask, “On the same riverside path, same weather, same pace, is my running power this month 8 watts lower than three months ago?” If so, that might mean your efficiency has improved (same speed, less effort)—that’s a valuable signal.

Principle Two: Put Data into “Context”

Running dynamics data is extremely sensitive to environment. Ground contact time lengthens on uphills, vertical oscillation changes; running power spikes into headwinds; in Taiwan’s hot, humid summer (like Dajia Riverside or Guandu Bikeway in July and August, with humidity often above 85%), your heart rate and perceived effort are elevated, so comparing that data to a cool winter day is apples to oranges.

I always require my students to log the day’s weather, route, and body condition in their watch app. Numbers without context are just noise.

Here’s a real example. A student preparing for Taipei Marathon, Xiao-Mei, messaged me one week, frustrated: “Coach, my running power dropped nearly 15 watts this week, and my ground contact time got longer. Am I regressing?” I first asked her three questions: Have you been sleeping well? Is work stress high? Is the route the same? She admitted she’d been working late into the night all week, severely sleep-deprived, and had switched from the flat riverside to the hilly Xiangshan trail for hill training. The answer wasn’t “regression”—it was sleep deprivation + a harder route, two contextual factors at play. I told her to train as usual, catch up on sleep, and the following week back on the riverside, all the data returned. If she had only looked at the numbers, panicked, and “changed her form,” that’s where real trouble would have started.

Principle Three: Look at the Three Metrics Together, Don’t Bet on Just One

This is the most common mistake—fixating on a single number and changing it. The right approach is to treat cadence, ground contact time, and vertical oscillation as an interconnected system.

Running Dynamics Metric	Common Range for Typical Runners	Usually “More Economical” Direction	Common Misconception
Cadence	160–180 spm	Naturally increases with speed	Forcing 180 across all paces
Ground Contact Time (GCT)	200–300 ms	Shorter, but achieved naturally	Deliberately landing on toes to force it shorter
Vertical Oscillation (VO)	6–11 cm	Smaller	Shortening stride and stiffening the body to lower it
Vertical Ratio (VR)	6%–13%	Lower	Ignoring it, only looking at absolute amplitude
Ground Contact Balance	Close to 50/50	Symmetrical left/right	Overinterpreting normal 1%–2% fluctuations

Here I want to specifically flag a subtle point from research: studies do indicate that imbalance in ground contact time between the two feet is associated with worse running economy (source at the end). But a “1% to 2% left-right difference” is completely normal physiological fluctuation for the vast majority of people. Don’t see 49/51 and think one leg is broken and go buy corrective insoles. What truly warrants attention is a persistent and significant asymmetry (e.g., chronically above 46/54), often accompanied by old injuries or strength imbalances—that’s when you should see a physical therapist, not buy a more expensive watch.

The Real Risk of Technique Modification: Slow Is Fast

Okay, enough groundwork. Let’s get to the hardest part—if you do decide to adjust your running form (increase cadence, shorten ground contact, lower oscillation), how do you do it without getting injured?

Let me pour some cold water on you first: Form modification is the highest-risk type of training there is. Why? Because you’re forcing your body to absorb impact forces in ways it’s not familiar with, and those forces get redistributed to tissues that aren’t ready for them.

The Classic Disaster: Changing to Forefoot Striking to Shorten Ground Contact Time

I’ve seen too many people read “shorter ground contact time is better” and start deliberately landing on their forefoot, running on their toes. The result? Ground contact time does get shorter, the watch numbers look great—and then two to three weeks later, the Achilles tendon and the posterior calf (gastrocnemius, soleus) start hurting, and in severe cases, Achilles tendinitis sets in.

The reason is simple: forefoot striking shifts more load to the Achilles tendon and calf muscles. Your cardiovascular system may already be trained, but your tendons adapt far more slowly than muscles and the cardiovascular system—tendons have poor blood circulation and long collagen remodeling cycles, often taking months. The speed at which your watch numbers improve far outpaces the speed at which your tissues adapt, and that gap is where injuries happen.

The Chain Reaction of Increasing Cadence

Increasing cadence is relatively safe and is the most commonly recommended first step—because a slightly higher cadence usually automatically shortens stride, reduces the braking effect, and incidentally lowers vertical oscillation. But even for such a “gentle” adjustment, I only recommend an increase of 5% at a time, no more.

Say your natural cadence is 168. The goal isn’t to jump straight to 180, but to first work toward around 176 (168 × 1.05 ≈ 176). Use a metronome app or your watch’s metronome feature, set it to 176, and start by adding it only to the last 10 minutes of each run, two to three times a week. Once your body adapts and it feels effortless, then consider the next step.

A Special Note for Triathletes: Technique Breakdown Under Fatigue

If you’re a triathlete, here’s a trap that pure road runners rarely encounter: your run always happens after swimming and cycling, with your body already significantly fatigued. This means the beautiful form you train in a “fresh state” may collapse in the final 10K of an Olympic-distance race, or the final stretch of a 226.

I’ve seen technically excellent athletes hold steady cadence and crisp ground contact for the first 5K, then as glycogen depletes and the core gives out in the later stages, cadence drops, ground contact time lengthens, the body starts bouncing around, the upper body leans forward and hunches—efficiency falls off a cliff. This isn’t “not learning the technique well enough”; it’s that the muscular endurance supporting the technique (especially core and glutes) collapses first under fatigue. So triathletes’ technique training must include “maintaining movement quality under fatigue”: occasionally place technique runs or cadence drills into transition runs after cycling, forcing the body to learn to hold form when tired. That’s far more practical than making the numbers look perfect when you’re freshest.

My “Four Principles of Technique Modification Risk Management” for All Students

1. Change only one variable at a time. You can’t simultaneously adjust cadence, foot strike, and forward lean without something breaking. If you’re changing cadence, focus only on cadence, and stabilize it for 4 to 6 weeks before anything else.
2. Don’t change by more than 5%. The body adapts strongly to progressive load but is fragile against sudden change.
3. Do technique work at low intensity and short distances. New movements should be practiced when you’re not tired, at slow pace, and short distance, so the neuromuscular system can build the pattern first. When tired, form breaks down, and you’ll be practicing bad habits.
4. Monitor “newly appearing” soreness. General post-training fatigue soreness is normal; but if it’s localized, specific, hurts more as you run, and recurs after rest (especially Achilles, anterior shin, plantar foot, or anterior knee), stop immediately and assess. That’s your body telling you load distribution has gone wrong.

I often tell my students: Form modification is a “month-scale” project, not a “week-scale” challenge. Those methods that promise a complete transformation in three weeks usually also deliver you to the clinic in three weeks.

Instead of “Changing Numbers,” “Train Movements”—Four Technique Drills I Use Most

I’ve emphasized throughout: good ground contact time and low oscillation are “trained into existence, happening naturally,” not “deliberately produced.” So what specifically should you train? Here are four foundational technique drills I prescribe to most students—low risk and effective. All of these go after warm-up, before the main session, with light, quick, relaxed movements. Better to do fewer than to do them until tired and broken down.

• Strides: On flat ground, run at 80%–90% of near-full speed for 15 to 20 seconds. The point isn’t speed, but feeling “high cadence, light ground contact, relaxed.” Walk fully for 60 seconds of rest, then repeat, for 4 to 6 reps. This is the best way to write “light and quick” into your neuromuscular memory.
• Bounding in place / jump rope: Bounce lightly and quickly on the forefoot, feeling the Achilles like a spring—“pop-bounce” rhythm. Ground contact should be short, the sound light. Do 30 seconds × 3 to 4 sets. This directly trains your stretch-shortening cycle.
• A-Skip: Alternately lift knees lightly and quickly, feet landing crisply, emphasizing rhythm and coordination rather than height. 20 meters × 4 reps. It improves your knee drive and foot strike timing.
• Glute bridge / single-leg glute bridge: This isn’t a run drill, it’s strength, but I put it here because weak glutes are the most common hidden culprit behind excessive vertical oscillation. If the glutes can’t hold the pelvis, the body compensates by “jumping up.” Do 12 to 15 reps per side × 3 sets.

I want to emphasize: the goal of these drills is not to make your watch numbers look better in the moment, but to build the physical conditions for “running light.” After a few weeks, you’ll find yourself running with more spring and less effort—and when you look back at the data then, it will already look good on its own.

Actionable Advice for Runners at Different Levels

After all this, you might ask: so should I touch my running form or not? I’ll break my advice into three categories by level.

Beginner Triathletes / New Runners: Don’t Touch Form Yet, Accumulate Volume First

If you’ve just started running, or are preparing for your first 51.5 triathlon, my advice is very clear: temporarily ignore the red running dynamics numbers on your watch. What you should do now is safely and injury-free accumulate running volume, letting your body build foundational aerobic capacity and tendon tolerance. At this stage, your efficiency will improve “naturally”—not because you changed anything, but because your body is adapting.

The only small thing you can do: if you feel each step is heavy, “thud, thud,” like stomping the ground, you can slightly try “higher cadence, shorter stride,” imagining you’re stepping on a hot pan, your feet lightly brushing the ground. That imagery alone usually lightens your movement without needing to stare at numbers.

Advanced Runners / Triathletes Chasing PBs: Optimize Systematically, One Thing at a Time

If you already have a solid volume base and want to compete in Olympic-distance or half marathon, you can start systematically optimizing technique. My recommended order is:

• First priority: Cadence. Use the “+5%, metronome, low-intensity at the end of runs” method described earlier. This has the highest return on investment and lowest risk.
• Second priority: Form strength and elasticity. Rather than “adjusting” ground contact time and oscillation, “train” them into existence. Core stability, glute activation, and calf/Achilles elasticity (e.g., progressive jump rope, bounding in place, quick light-contact technique drills) will make short ground contact and low oscillation happen naturally, not be forced.
• Third priority: Only then, targeted fine-tuning. And this should be done with the help of a coach or gait analysis.

Below is a sample “cadence optimization weekly schedule” I often give advanced students, to give you a concrete picture (assuming your current natural cadence is about 168, target stage 176):

Day	Workout Content	Cadence Handling	Focus
Mon	Rest / cross-training (swim or bike)	—	Recovery, let tendons rest
Tue	Easy run 40 min	Last 10 min at 176 spm	Implant new cadence at low intensity
Wed	Technique drills + 4×20 sec strides	Feel high cadence during strides	Neuromuscular activation
Thu	Aerobic run 50 min	“Natural, slightly higher” throughout, don’t look at watch	Avoid over-controlling
Fri	Rest	—	Recovery
Sat	Tempo run 6 km	176–180 spm during tempo segment	Consolidate at moderate intensity
Sun	Long slow run 90 min	Natural early, lightly carry cadence late	Maintain movement quality under fatigue

Note that in this table, cadence intervention is “spot” based, not staring at it the whole time. The goal is to let the body slowly internalize the new cadence as its default, rather than forcing it through willpower the entire run. After 4 to 6 weeks, you’ll find that even without looking at the watch, your natural cadence has quietly crept up.

Veteran / Kona-Level Athletes: Data Is a Fine-Tuning Tool, Not a Faith

At this level, running dynamics data’s value actually returns—because your form is already stable, so subtle changes (e.g., ground contact balance drifting in late fatigue, vertical oscillation rising in long races) can provide useful fatigue and pacing information. But you also know best: these are fine-tuning references, not absolute values to chase. What you’re chasing is “running faster within a given physiological cost,” not “making some number turn green.”

FAQ (Questions I Get Most Often from Students)

Q: My heart rate is actually higher when I run at a higher cadence. Is that normal?
When you first start adjusting cadence, the movement isn’t yet smooth, and your muscles are doing a lot of extra micro-adjustment work, so a temporary heart rate increase is normal. But if after 3 to 4 weeks you’re still noticeably more tired and breathless, you’ve likely pushed the cadence too high, beyond what your current speed calls for. Back off a bit and let it sit closer to natural. Remember the speed-cadence table earlier: cadence follows pace. You wouldn’t hold interval cadence at recovery pace—that would only unnecessarily raise your heart rate, turn an easy run into moderate intensity, and defeat the purpose of the session.

Q: My vertical oscillation just won’t come down. What should I do?
Don’t “deliberately suppress” oscillation—many people, trying to lower it, unconsciously shorten their stride, tense up, or even hunch, which makes things worse. Oscillation is an “outcome” of core stability and lower-limb elasticity. Train your core, train your glutes, train your bounce, and oscillation will come down on its own. Directly attacking the outcome usually just buys you stiffness.

Q: My watch says my left-right ground contact is imbalanced. Should I get insoles or see a doctor?
If it’s just a 1%–2% fluctuation, ignore it—that’s normal. But if it’s persistent and significant (chronically above 46/54), and that side happens to have an old injury or is clearly weaker, it’s worth getting a professional assessment—but start with a physical therapist or sports medicine physician for movement and strength testing, not by spending money on gear first.

Q: In a triathlon, right after getting off the bike and transitioning to the run, my cadence and form are all over the place. Is that normal?
Very normal. This is the triathlon-specific “brick” challenge. Right after dismounting, blood flow distribution in the legs hasn’t switched over yet, the muscles are in “cycling mode,” cadence tends to be low, and movement feels clunky. My advice here isn’t to fight it, but to use “deliberately higher cadence, shorter stride” to help the body switch quickly—run the first 1 to 2 km with short, light, high-cadence steps, which actually accelerates you into your running rhythm. This is also why transition runs (bike immediately followed by run) must be practiced, so the body gets familiar with the switch.

Q: Can barefoot shoes / minimalist shoes improve my running form?
They “might” naturally guide you to shorten stride, increase cadence, and change foot strike, because with less cushioning, you’ll subconsciously run lighter. But—this is exactly the high-risk zone. Switching directly from regular running shoes to minimalist shoes is like changing your landing mechanics all at once, dumping a huge load onto an unprepared Achilles and plantar foot. If you really want to try, you must transition at an ultra-slow “month-scale” pace, starting with just a few hundred meters per session, and stay highly alert to Achilles and plantar soreness. Don’t let a pair of shoes do the dangerous thing of “changing too much at once” for you.

Q: So should I care about this data at all?
Yes, but in the right way. Treat it like a “health checkup report”—review trends regularly, dig deeper when something abnormal appears, but don’t stare at one number and obsess daily. Your goal is to stay injury-free, improve, and enjoy running—not to get a full row of green lights from your watch app.

Q: I’m older (40+) and just started taking running seriously. Are these technique modifications still suitable for me?
Suitable, but risk management needs to be more conservative. As we age, tendon collagen remodeling is slower and recovery is slower, so the “+5%, month-scale, one variable at a time” principles I mentioned aren’t suggestions for you—they’re iron rules. Spend more time on strength (especially glutes and core) and strides, and less on aggressive foot strike changes. Your advantage is patience and discipline—apply those in the right places, and you’ll still progress steadily.

Conclusion: Let the Body Lead, Let Data Follow

Back to A-Kai at the beginning. In the end, I didn’t have him chase 180. The first thing we did was turn off all the red-flag warnings in his watch app, letting him quietly accumulate volume and build up his core and glutes. Four months later, his natural cadence had slowly moved from 172 to 178, ground contact time was shorter, oscillation was lower—but these “happened,” they weren’t “chased.” More importantly, he went through that entire season injury-free and set a new half marathon PB at Taipei Marathon.

The one sentence I want to leave you with is: Cadence, ground contact time, and vertical oscillation are the “dashboard” of your body’s efficiency, not the “steering wheel.” The dashboard tells you your current state, but the one truly holding the steering wheel is always the training you’ve solidly accumulated, the strength and elasticity you’ve progressively built, and your listening to your body’s signals.

Numbers are honest, but numbers are also easily misread and misused. When you stop being held hostage by the colors on your watch and start viewing them through trends, context, and progression, you truly transform from “someone chased by data” into “someone using data to make themselves stronger.”

Taiwan’s running environment is wonderful—from the cool riverside paths at dawn, to the hot, humid afternoons that test your will, to the marathons one after another in autumn and winter. These real roads, weathers, and races are where your technique is truly forged, far more important than any number on a watch. The hot, humid summer teaches you the discipline of pacing and hydration; the rolling mountain trails force out your strength and core; the cool autumn and winter race courses let you reap the harvest of a year’s accumulation. Take it slow, train steadily, and let good technique ripen like fruit, maturing naturally at the right time. Next time you open your watch and see a row of red numbers, take a deep breath and remind yourself: that’s just the dashboard. The one holding the steering wheel is always you, not the watch. Wishing you run light, run long, and run happy—see you on the race course.

This article is educational content and cannot replace individual assessment by a physician, physical therapist, or nutritionist.

References

• Running Cadence: The Science Behind the 180 SPM Myth — https://aboutrun.com/running-cadence-science-180-spm-myth/
• Running Cadence: What It Is, Why It Matters and How To Improve It (RunRepeat) — https://runrepeat.com/guides/what-is-running-cadence
• The implications of time on the ground on running economy: less is not always better (Journal of Experimental Biology) — https://journals.biologists.com/jeb/article/222/6/jeb192047/20709/The-implications-of-time-on-the-ground-on-running
• Ground Contact Time Imbalances Strongly Related to Impaired Running Economy (PMC) — https://pmc.ncbi.nlm.nih.gov/articles/PMC7241633/

Related Reading

• Debunking the 180 Cadence Myth: Finding Your Optimal Cadence
• Vertical Oscillation and Ground Contact Time: Two Key Metrics of Running Efficiency
• Running Efficiency Training: Methods for 180 spm Cadence and Metronome Use
• Interpreting Garmin Running Dynamics Data: Training Applications of Vertical Oscillation, Ground Contact Time, and Stride Length