Appke Watch fall detection quit working. How do I restart and make sure it is functioning reliably?

I often hike and bike solo and upgraded from an Apple Watch 3 to a 6 specifically for the fall detection. It worked when I first bought it - it detected a fall on my mtn bike. But in the past 3 weeks I’ve had 3 falls while walking and hiking and none were detected despite being much harder falls than the mtn bike fall. I checked settings - fall detection is on and my age (58) correct. Fortunately scrapes and bruises were the only injuries till now but Apple has really let me down.