America-based sprinter Khristel Martindale is the lone female named in the four-member junior Barbados squad for the Pan American Under-20 Championship this Friday to Sunday, in Mayaguez, Puerto Rico. Martindale, 19, is joined by fellow sprinters Amari Knight, Aragorn Straker and hurdler Nikkolia Kennedy, who will be accompanied by head coach Bryan Holder. After a below-par showing of 12.03 seconds in the women's 100 metres at last month's Barbados National …