| POS | BIB | ATHLETE | COUNTRY | MARK | Reaction Time | 
|---|---|---|---|---|---|
| 1 | SUI | Switzerland U20 | 
                                         
                                        SUI
                                     | 
                                    44.88 Q SB | 0.192 | 
| 2 | CAN | Canada U20 | 
                                         
                                        CAN
                                     | 
                                    45.23 Q SB | 0.195 | 
| 3 | UKR | Ukraine U20 | 
                                         
                                        UKR
                                     | 
                                    45.26 q | 0.162 | 
| 4 | ESP | Spain U20 | 
                                         
                                        ESP
                                     | 
                                    45.84 | 0.188 | 
| 5 | CHI | Chile U20 | 
                                         
                                        CHI
                                     | 
                                    46.15 | 0.156 | 
| 6 | ECU | Ecuador U20 | 
                                         
                                        ECU
                                     | 
                                    47.43 | 0.243 | 
| GER | Germany U20 | 
                                         
                                        GER
                                     | 
                                    DNF | 0.188 | |
| GBR | Great Britain & NI U20 | 
                                         
                                        GBR
                                     | 
                                    DQ | 0.175 | 
| POS | BIB | ATHLETE | COUNTRY | MARK | Reaction Time | 
|---|---|---|---|---|---|
| 1 | USA | United States U20 | 
                                         
                                        USA
                                     | 
                                    44.22 Q SB | 0.169 | 
| 2 | AUS | Australia U20 | 
                                         
                                        AUS
                                     | 
                                    44.76 Q | 0.170 | 
| 3 | POL | Poland U20 | 
                                         
                                        POL
                                     | 
                                    45.00 q | 0.153 | 
| 4 | IND | India U20 | 
                                         
                                        IND
                                     | 
                                    45.31 NU20R | 0.199 | 
| 5 | RSA | South Africa U20 | 
                                         
                                        RSA
                                     | 
                                    46.61 SB | 0.133 | 
| 6 | PER | Peru U20 | 
                                         
                                        PER
                                     | 
                                    49.31 | 0.209 | 
| TTO | Trinidad and Tobago U20 | 
                                         
                                        TTO
                                     | 
                                    DQ | 0.183 | |
| HUN | Hungary U20 | 
                                         
                                        HUN
                                     | 
                                    DNS | 
| POS | BIB | ATHLETE | COUNTRY | MARK | Reaction Time | 
|---|---|---|---|---|---|
| 1 | JAM | Jamaica U20 | 
                                         
                                        JAM
                                     | 
                                    43.81 Q | 0.162 | 
| 2 | PUR | Puerto Rico U20 | 
                                         
                                        PUR
                                     | 
                                    45.28 Q NU20R | 0.184 | 
| 3 | ITA | Italy U20 | 
                                         
                                        ITA
                                     | 
                                    45.55 | 0.183 | 
| 4 | SLO | Slovenia U20 | 
                                         
                                        SLO
                                     | 
                                    45.63 NU20R | 0.162 | 
| 5 | BOT | Botswana U20 | 
                                         
                                        BOT
                                     | 
                                    46.43 NU20R | 0.186 | 
| NGR | Nigeria U20 | 
                                         
                                        NGR
                                     | 
                                    DQ | 0.174 | |
| FRA | France U20 | 
                                         
                                        FRA
                                     | 
                                    DQ | 0.169 | |
| BRA | Brazil U20 | 
                                         
                                        BRA
                                     | 
                                    DQ | 0.193 |