adidas UltraBoost 21 - White/Black - UK 9

The Primeknit upper offers a degree of adaptability, but individuals with significantly wide feet may find them snug. It is recommended to try them on if possible or consider sizing up if you prefer a roomier fit.

For the white areas, a soft brush with a mixture of mild soap and water can be effective. For stubborn marks, a magic eraser can be used with caution, but always test on an inconspicuous area first.

The Boost midsole is known for its durability and resistance to temperature changes. While mileage varies based on usage, many runners find the cushioning remains effective for several hundred miles.

Yes, the cushioning and stable base make them suitable for some gym activities. However, for dedicated weightlifting or sports requiring lateral stability, a more specialized shoe might be preferred.

The UltraBoost 21 features an updated Boost midsole for enhanced energy return, a new outsole design for improved grip, and a refined Primeknit upper for a more adaptive fit compared to earlier versions.

Generally, the UltraBoost 21 runs true to size for most runners. However, foot shape and sock thickness can influence perceived fit. Refer to the sizing chart and consider trying them on if possible.

Loosen the laces and adjust the fit. The Primeknit upper will adapt to your foot over time with wear.

Ensure the Boost midsole is clean. While durable, extreme dirt can slightly affect the feel. Allow for a break-in period if the shoes are brand new.

Check that the laces are tied securely. Ensure the outsole is free from excessive mud or debris. The outsole is designed for traction on typical running surfaces.