Stop guessing your zones. Stop leaving free speed on the table. Each assessment is built to identify your real limiter, technique, drag, economy, aerobic capacity, recovery, or fueling, and turn it into clear next steps.
Testing is most useful when it answers the questions that matter: what is limiting performance, where the biggest gains are, and what to prioritise next.
Sometimes the answer is physiology. Sometimes it's technique. Sometimes it's drag. A good assessment cuts through the noise.
Better zones, better pacing, sharper priorities. Practical decisions on training load, fueling, and equipment instead of guesswork.
The point isn't to measure once. It's to confirm whether training, technical work, and setup changes are actually moving performance.
The three services that connect most directly to visible performance gains, and the easiest places to start.
Find the technique issues costing you speed in the water. Body position, catch, breathing, propulsion vs drag, reviewed with clear correction priorities, not vague advice.
Real-world watt savings without throwing more money at gear. Live CdA readings on out-and-back rides isolate which changes, helmet, position, tires, hydration setup, actually save you time on race day.
Field tests and wearables estimate. A graded ramp with breath-by-breath gas exchange measures, lab-verified VO₂max, real ventilatory thresholds, and zones built from your own data, not someone else’s chart.
The full Performance Lab catalog, technique work to improve how you move, physiology testing to improve how you train.
Three ways in: send video for a remote breakdown, meet poolside for a 30-min deck-side session, or go deep with HD video plus wearable force-mapping sensors. Each tier targets the same core idea, stop technical issues from costing you speed.
Ideal for: triathletes who feel slow in the water, swimmers who’ve plateaued, and anyone whose stroke has never been filmed.
Real-world watt savings without throwing more money at gear. Out-and-back rides with a live aero sensor and your power meter (loaner available). Each test isolates one change, helmet, hand position, hydration, tire pressure, so you know exactly what saved time.
Ideal for: long-course triathletes, time-trial riders, breakaway-minded roadies, and anyone debating equipment upgrades.
Improve how you move, reduce injury risk, and convert more force into forward motion. Three depths: a remote video review, a 30-min trackside session, or a 60-min biomech deep dive paired with VO₂ and SmO₂ data.
Ideal for: runners battling recurring injuries, triathletes whose run leg falls apart late, masters athletes wanting to stay durable, and serious racers chasing margin.
Most athletes feel lighter on their feet within a few sessions. Meaningful efficiency gains and injury-risk reduction show up over 8–12 weeks of consistent drill work.
Your VO₂max is a direct window into how efficiently your body transports and uses oxygen at peak effort. Field tests and wearables estimate. A graded ramp with breath-by-breath gas exchange measures, and gives you zones built from your own data.
Ideal for: endurance athletes chasing PRs, multi-sport athletes comparing run vs. bike, health-focused clients wanting an objective marker, and coaches building data-driven plans.
Generic formulas can miss your true Resting Metabolic Rate by 15–25%. We measure it directly with medical-grade gas analysis, so calorie targets, fueling, and recovery decisions sit on actual data.
Ideal for: endurance athletes fine-tuning fueling, strength athletes chasing lean mass without under-eating, anyone rebounding from injury or over-training, masters athletes tracking age-related metabolic change.
If results flag elevated RED-S risk, we outline referral options (sports dietitian, blood work) and a re-test timeline.
Sprint, recover, repeat, that’s the coin of the realm in HYROX, CrossFit, criteriums, and short-course triathlon. The PRP measures how hard you can surge and how fast you bounce back, so you pace attacks and intervals on data, not feel.
Ideal for: HYROX and CrossFit athletes hammering repeats, road racers and crit specialists, short-course triathletes, and tactical/team-sport athletes who live on burst-recovery patterns.
The deepest physiological scan we run. One session, several data streams, all synchronized, to pinpoint exactly where your performance breaks down and how to fix it.
Ideal for: competitive endurance athletes eyeing podiums or qualifiers, hybrid athletes (HYROX, XTERRA) who need clarity on both endurance and power, and coaches who want a single unified dataset instead of piecemeal results.
Not sure which assessment fits? Use the contact form or email info@yousuli.co with your goal, we’ll match you to the right starting point.
Testing comes to you, locally around Walnut, CA, and on the road when scheduling and travel align.
Free mobile testing around Walnut, California. Can run testing days at gyms, studios, swim schools, and clubs across greater Los Angeles. Throughput up to ~8 tests / day.
Beyond the local area, travel fees apply unless waived by same-day or weekend blocks.
Travel fees may be reduced or waived when booking aligns with the existing event calendar, UCI Irvine Zot Trot, Stanford Treeathlon, UCSD Tritonman, Wildflower, IM70.3 Northern California, UCSB, IM70.3 Indian Wells, UCLA / Santa Monica trips.
If your race is on the calendar, ask, we may already be on location.
How to choose a test, who these services are for, and what to expect from the process.
Start with the assessment that matches your clearest bottleneck. Technique issues usually point to swim stroke, gait, or aero testing. Training-zone uncertainty points to VO₂max. Fueling questions point to RMR.
No. Some services are advanced, but several entry points work well for age-group athletes who simply want clearer answers and smarter decisions. Beginners are explicitly welcome.
Yes. Common combos: VO₂max + RMR for full metabolic, or Swim Stroke + Bike CdA for technique-focused free speed. PRO Full-Stack Profiling bundles the deeper physiology stack.
That’s the standard. Every test produces a one-page summary for the athlete (zones, pacing, fueling, priorities, limiter diagnosis) plus a deeper technical appendix for the coach.
VO₂max ~45 min test + ~15 min debrief. Swim, gait, and CdA are typically 60–90 min on-site. Full-stack profiling can take a half-day depending on the protocol.
Yes. Yousuli has a Supported Athletes program with reduced-rate coaching and assessment support for committed elite and para-athletes. Email us with your goals.
Book the assessment that matches your current limiter, or start with a best seller for the clearest entry point. Mobile lab travels, we may already be near you.
All services are bookable individually above. Coached athletes & YSC Performance Tier members save 20%, sign in at booking to apply.
