As for Garmin Connect, it offers the activity detailed api for developers to access the everysec detailed in a certain activity as a json. I wander whether Strava v3 API offer the same, because I cannot find this information in API Docs.
The Activity Detailed is as follow:
"samples": [{
"startTimeInSeconds": 1695538280,
"bikeCadenceInRPM": 0.0,
"timerDurationInSeconds": 0,
"movingDurationInSeconds": 0,
"heartRate": 99,
"elevationInMeters": 3.200000047683716,
"speedMetersPerSecond": 1.8940000534057617,
"latitudeInDegree": 22.55610477179289,
"clockDurationInSeconds": 0,
"longitudeInDegree": 113.87656951323152,
"airTemperatureCelcius": 35.0,
"totalDistanceInMeters": 0.029999999329447746
}, {
"powerInWatts": 0.0,
"longitudeInDegree": 113.87656565755606,
"totalDistanceInMeters": 1.9199999570846558,
"startTimeInSeconds": 1695538281,
"bikeCadenceInRPM": 0.0,
"timerDurationInSeconds": 1,
"movingDurationInSeconds": 1,
"heartRate": 99,
"elevationInMeters": 3.0,
"speedMetersPerSecond": 1.8940000534057617,
"latitudeInDegree": 22.55609999410808,
"clockDurationInSeconds": 1,
"airTemperatureCelcius": 35.0
},