One of the great strengths of the market strength indicator (MSI) is in how it visually describes those relationships that reveal so much across markets or instruments.
In this case, on the TradingView platform, David shows the market strength indicator in action for index futures along with the VIX, which is a classic inverse relationship that the indicator then describes. In this example he uses ETF indices with the SPY, QQQ, DIA and IWM.