Running GPS Watch Features Explained: Heart Rate, Cadence, Vertical Oscillation

Modern GPS running watches provide more and more data: heart rate, cadence, stride length, vertical oscillation, ground contact time… What do these numbers mean? And how can you use this data to improve your running? This article breaks it all down.

Basic Running Data

Pace

Time per kilometer (min:sec/km), the most basic and commonly used metric.

Common pace references for Taiwanese runners:

• Within 5:30/km: Advanced runner, marathon close to 3 hours 30 minutes
• 6:00/km: Intermediate level, marathon around 4 hours 15 minutes
• 7:00/km and above: Beginner or easy run pace

Cadence (Steps Per Minute, SPM)

Steps per minute, an important indicator of running efficiency.

Why is cadence important?

• Low cadence (<160 SPM) is usually accompanied by a long stride, increasing heel-strike impact and raising injury risk
• 180 SPM has long been the target value recommended by coaches (based on Jack Daniels’ research)
• In reality, the ideal cadence varies by height and running speed; 170-185 SPM is a reasonable target range for most runners

Ways to increase cadence:

• Use a metronome (most watches have this feature) to set a target cadence
• Increase gradually each week (increase by 5% at a time to avoid injury)
• Shorten your stride and increase leg turnover

Heart Rate Data

Heart Rate (HR)

The most basic physiological monitoring metric, reflecting exercise intensity.

Maximum heart rate estimation:
Traditional formula: 220 - age (larger margin of error)
More accurate Tanaka formula: 208 - (0.7 × age)

Heart rate training zones (based on maximum heart rate):

Zone	HR %	Feeling	Training Effect
Zone 1	50-60%	Very easy	Recovery, base aerobic
Zone 2	60-70%	Easy, can hold a conversation	Aerobic base building
Zone 3	70-80%	Moderate, hard to converse	Aerobic capacity improvement
Zone 4	80-90%	Hard, cannot speak	Lactate threshold training
Zone 5	90-100%	Maximum effort	VO2 Max, anaerobic capacity

The 80/20 Rule: Modern endurance training research suggests that spending 80% of training time in Zones 1-2 (low intensity) and 20% in Zones 4-5 (high intensity) is the optimal ratio for performance improvement.

Heart Rate Variability (HRV)

The variation in time intervals between consecutive heartbeats, the best physiological indicator of recovery status.

• High HRV: Good sympathetic/parasympathetic balance, good recovery status, suitable for high-intensity training
• Low HRV: Body is in a stressed/fatigued state, low-intensity training or rest is recommended

Most top-tier watches (Garmin, Polar, COROS) automatically measure HRV during sleep and provide training recommendations in the morning.

Running Dynamics

Running dynamics are advanced analytical metrics that typically require a chest-strap HRM sensor (such as the Garmin HRM-Pro) for accurate measurement.

Vertical Oscillation

The vertical distance your body’s center of mass travels during running (in centimeters).

Ideal range: 6-9 cm (elite runners typically 5-7 cm)

Significance: The smaller the vertical oscillation, the more energy is used for forward motion rather than bouncing up and down. Excessive vertical oscillation is usually accompanied by:

• Heel striking
• Low cadence
• Insufficient core strength

How to improve: Increase cadence, strengthen your core, imagine a ceiling above your head limiting vertical movement

Ground Contact Time (GCT)

The time each foot spends on the ground per step (in milliseconds).

Ideal range: 200-280 ms (elite runners typically 160-200 ms)

Significance: The shorter the ground contact time, the more elastic your running is, and the more efficiently you transmit ground reaction forces.

Causes of long ground contact time:

• Heavy heel striking
• Insufficient propulsion from the hips and ankles
• Excessive fatigue

Ground Contact Time Balance

The ratio of the difference in ground contact time between the left and right feet. The ideal value is close to 50/50. If the difference exceeds 2-3%, it may indicate an imbalance on one side that needs attention.

Stride Length

The forward distance covered per step (in meters). Together with cadence, it determines running speed:

Speed = Stride Length × Cadence

Speed can be improved by increasing cadence (lower injury risk) or increasing stride length (requires greater muscular strength and flexibility).

VO2 Max Estimation

VO2 Max is maximal oxygen uptake, representing the upper limit of cardiorespiratory function. Watches calculate an estimate based on the relationship between heart rate and pace. It is less accurate than laboratory testing but has reference value for tracking long-term trends.

Reference ranges for general Taiwanese runners:

Level	VO2 Max	Marathon Goal
Beginner	35-40	Over 5 hours
Intermediate	45-50	4-4.5 hours
Good	50-55	3.5-4 hours
Excellent	55-60	3-3.5 hours
Elite	60+	Sub-3

How to Effectively Use Watch Data

Daily Training

1. Set heart rate zones to ensure easy runs are truly easy (Zone 2)
2. Record morning resting heart rate once a week to track recovery status
3. Pay attention to cadence and gradually increase it to 170-180 SPM

Pre-Race Assessment

1. Measure HRV for 7 consecutive days to determine peak readiness
2. Observe heart rate drift (Cardiac Drift) during long-distance training

Don’t Over-Rely on the Data

Watch data is a supporting tool; subjective feeling is equally important. If you feel great today but HRV is low, you can appropriately reduce training intensity as circumstances warrant, but you don’t need to base every decision entirely on the numbers.

Recommended Watches (by Budget)

Budget	Recommendation	Supported Dynamic Metrics
NT$5,000-8,000	Garmin Forerunner 255	Heart rate + basic cadence
NT$8,000-12,000	Garmin Forerunner 955	Full running dynamics (requires HRM Pro)
NT$12,000+	Polar Vantage V3	Most accurate heart rate + running power

Conclusion

Running watch data capabilities are becoming increasingly powerful, but the most important thing is to understand the meaning behind the data and translate it into actual training improvements. Start with the most basic heart rate zones, gradually add attention to cadence and vertical oscillation, and let the data become your best coach for running progress.

Related Reading

• Garmin Running Dynamics Data Explained: Training Applications of Vertical Oscillation, Ground Contact Time, and Stride Length
• Vertical Oscillation and Ground Contact Time: Two Key Indicators of Running Efficiency
• Vertical Oscillation Optimization: Reducing Energy Waste in Every Step
• Complete Running Heart Rate Guide: Resting Heart Rate, Maximum Heart Rate, Aerobic Heart Rate