Today’s Plan closed permanently on March 12, 2024. Many comparison articles still treat it as a live product — so if you landed here looking to replace it, that’s the situation. What it got right was unified multisport load modeling: a single Performance Management Chart across swim, bike, and run with per-sport thresholds. That problem hasn’t gone away. Most platforms still handle it poorly.
What Today’s Plan Got Right About Multisport Load
Today’s Plan used a metric called TScore — functionally equivalent to TSS (Training Stress Score), the load currency developed by Andy Coggan and Hunter Allen. One hour at your threshold equals 100 TSS.
What made it distinctive was the presentation layer. A triathlon brick appeared as one unified activity. Each segment was color-coded by sport. Each had its own summary metrics. You saw the whole workout as one physiological event.
It also tracked CTL (fitness score) and ATL (fatigue score) per sport. When Specialized shut it down, they cited the economics of competing with TrainingPeaks. Roughly 50,000 athletes needed a new home. The core problem they were solving — cross-sport load management — didn’t migrate easily.
The Core Problem: Multisport Load Is Not One Number
Your fitness score (CTL) is a 42-day exponentially weighted moving average of daily TSS. Your fatigue score (ATL) covers 7 days. Your form score (TSB) is CTL minus ATL.
These time constants come from Banister’s impulse-response model, developed for single-sport athletes. Every major platform applies them regardless of sport. A triathlete with combined CTL of 100 looks identical whether they’re doing 80 cycling + 15 running + 5 swimming, or 40 of each. They aren’t.
Running loads your joints at roughly 250% of body weight per stride. Cycling and swimming don’t load weight-bearing structures at all. The injury data proves the body knows the difference even when the math doesn’t.
Running causes 71.5% of all triathlon training injuries despite typically being the shortest discipline by hours. Swimming accounts for just 10.8%. A 2022 systematic review of 5,996 triathletes confirmed this pattern. A 2025 cross-sectional study of 758 Brazilian triathletes found 56% reported a musculoskeletal injury in the past year. Athletes training for 70.3 had 68.6% higher odds of injury versus shorter distances.
Running TSS doesn’t equal cycling TSS. The number says they do.
How TSS Is Actually Calculated Across Three Sports
Cycling TSS uses power:
TSS = hours × IF² × 100
Where IF = Normalized Power divided by FTP.
Running TSS (rTSS) uses the same structure with pace substituted. IF = Normalized Graded Pace divided by threshold pace.
Swim TSS (sTSS) is different — it cubes the intensity factor:
sTSS = IF³ × hours × 100
Where IF = Normalized Swim Speed divided by CSS (Critical Swim Speed) — your lactate threshold pace in the water, from a 200m and 400m time trial. The cube accounts for water’s higher resistance at speed. At high swim intensity, load compounds faster than on the bike or run.
You can’t calculate meaningful sTSS without a CSS test. Most athletes don’t do one. Read more about how to set swim threshold pace with the CSS test.
Mini Case Study: The Running Spike a Combined CTL Missed
Consider Tom, 42, training for his second 70.3. He’s been consistent for 18 weeks. His combined CTL has climbed from 55 to 78. His platform shows form score around -15 — no alerts.
In week 19, he adds a second long run. His weekly run volume jumps from 28 miles to 41 miles. Bike and swim volumes don’t change.
His combined CTL ticks up by 4 points. Safe, by any ramp-rate standard.
Six days later, he has a stress fracture in his left tibia.
His run-specific ACWR — the ratio of his 7-day running load to his 28-day running load — hit 1.8 that week. ACWR above 1.5 is where injury risk rises sharply, and above 2.0, risk is 4 to 8 times higher per Gabbett’s 2016 BJSM meta-analysis. His combined number looked fine because stable bike and swim loads diluted the spike.
A platform tracking per-sport load would have flagged it.
The ACWR Sweet Spot: Useful But Not Gospel
The ACWR (Acute-to-Chronic Workload Ratio) is your 7-day load divided by your 28-day average. The widely cited safe zone is 0.8 to 1.3. Above 2.0, multiple studies show 4 to 8 times higher injury risk.
But a 2020 Frontiers in Physiology study found 83.3% of injuries in elite pentathletes occurred within the supposed sweet spot. Mean injury count inside the sweet spot was nearly identical to the high-load zone.
ACWR is a yellow flag, not a tripwire. Calculating it per sport — not as one combined number — is what makes it useful for triathletes. Read more about ACWR and workload management.
Race-Day Load Targets by Distance
| Distance | Race-Day TSS | Target Peak CTL | Safe Weekly Ramp | Taper TSB Target |
|---|---|---|---|---|
| Sprint | 75–120 | 50–70 | 3–5 pts/wk | +10 to +20 |
| Olympic | 170–220 | 65–90 | 3–6 pts/wk | +10 to +20 |
| 70.3 | 300–400 | 80–120 | 4–7 pts/wk | +15 to +25 |
| Ironman 140.6 | 590–750 | 100–165+ | 5–8 pts/wk | +15 to +25 |
The safe ramp rate is 3 to 8 CTL points per week. Rates above 8 are consistently linked to injury or burnout. Read more about how CTL, ATL, and TSB interact in the Performance Management Chart.
How Platforms Actually Handle Multisport Load
| Platform | Load Metric | Per-Sport Thresholds | Auto Plan Adjustment | Status |
|---|---|---|---|---|
| Today’s Plan | TScore (TSS equiv.) | Yes (FTP, threshold pace, CSS) | Not documented | CLOSED March 2024 |
| TrainingPeaks | TSS / rTSS / sTSS | Yes, requires manual setup | No | Active — industry standard |
| Intervals.icu | TSS / hrTSS / TRIMP | Yes, adjustable per-sport % | No | Active — free tier |
| Garmin Connect | EPOC-based Acute Load | VO2max estimate only | No | Active — device-dependent |
| AthleteOS | TSS / rTSS / sTSS per workout script | Yes, FTP + threshold pace + CSS | Yes, trims plan on spike | Active — AI-driven |
TrainingPeaks is the industry standard. Per-sport PMC works well but requires manual configuration, and there’s no automatic plan adjustment when your running load spikes. A 2024 pilot study of age-group triathlon coaches found they ignored 75% of ATL spike alerts — and when they did act, prevented run spikes only 9% of the time.
Intervals.icu is free and configurable. You can set sport contribution percentages, which is the closest a free tool gets to true per-sport load tracking. No auto-plan adjustment.
Garmin’s EPOC-based load isn’t calibrated to your FTP or threshold pace. Two athletes with the same reading could be in very different physiological states. Learn more about FTP testing and what threshold means for cyclists.
AthleteOS calculates TSS, rTSS, and sTSS from each workout’s script using per-sport thresholds. It tracks fitness and fatigue across all three disciplines simultaneously. When any sport’s load ratio crosses the safe threshold, the upcoming week adjusts automatically. The AI coach handles it — you don’t need to catch the alert yourself.
What Good Multisport Load Modeling Actually Requires
Think of your training load as three fuel tanks feeding one engine. Each refills at a different rate and drains a different system. A leaky running tank is invisible if you only look at the combined gauge.
A solid platform needs four things: per-sport thresholds, per-sport CTL/ATL tracking, ACWR monitoring by sport, and automatic plan response. Today’s Plan was ahead on the first two. Modern platforms need all four.
If you’re rebuilding your setup after Today’s Plan closed, start a free AthleteOS account — the free tier covers per-sport load tracking with automatic load adjustment built in.