straight to your inbox every day, freeDean Henderson having impact on David de Gea in Manchester United training Dean Henderson has improved David de Gea’s training performances at Manchester United . De Gea, 29, has endured a difficult start to the campaign, but the MEN understands the United coaching staff feel the Spaniard’s training form has improved since Henderson arrived.It has also seen United goalkeeping coach Richard Hartis modify De Gea’s warm-up routine before games.