These are essentially trend following strategies, on the asset class level. When the stock market is going up, they allocate more towards stocks, when they're going down, they allocate more towards bonds.
When the strategies work, the switching between risky and more defensive assets reduces your timing risk, and enhance your returns. But, you’re also more concentrated (and less diversified) at any given time, resulting in underperformance when the strategies don't work.
These strategies will underperform if the market "can't decide whether it's going up or down", or in an event of a sudden crash-recovery like in 2020.
Typically rebalances monthly.