| POS | ATHLETE | COUNTRY | MARK | Reaction Time | 
|---|---|---|---|---|
| 1 | Great Britain & N.I. Junior |  GBR | 39.84 Q SB | 0.166 | 
| 2 | Japan Junior |  JPN | 39.95 Q SB | 0.150 | 
| 3 | Thailand Junior |  THA | 40.16 q SB | 0.156 | 
| 4 | Italy Junior |  ITA | 40.41 SB | 0.296 | 
| 5 | Poland Junior |  POL | 40.61 SB | 0.132 | 
| 6 | France Junior |  FRA | 40.83 SB | 0.236 | 
| 7 | Turkey Junior |  TUR | 41.65 NJ | 0.207 | 
| POS | ATHLETE | COUNTRY | MARK | Reaction Time | 
|---|---|---|---|---|
| 1 | Jamaica Junior |  JAM | 39.62 Q WJL | 0.175 | 
| 2 | Chinese Taipei Junior |  TPE | 40.16 Q NJ | 0.163 | 
| 3 | Czech Republic Junior |  CZE | 40.60 NJ | 0.157 | 
| 4 | Sweden Junior |  SWE | 40.72 SB | 0.179 | 
| 5 | Nigeria Junior |  NGR | 40.74 SB | 0.191 | 
| 6 | Canada Junior |  CAN | 41.33 SB | 0.165 | 
| Germany Junior |  GER | DNF | 0.205 | 
| POS | ATHLETE | COUNTRY | MARK | Reaction Time | 
|---|---|---|---|---|
| 1 | United States Junior |  USA | 39.37 Q WJL | 0.175 | 
| 2 | South Africa Junior |  RSA | 39.59 Q NJ | 0.160 | 
| 3 | Trinidad and Tobago Junior |  TTO | 40.40 q SB | 0.161 | 
| 4 | Russia Junior |  RUS | 40.43 SB | 0.126 | 
| 5 | Austria Junior |  AUT | 40.80 SB | 0.131 | 
| 6 | Senegal Junior |  SEN | 42.44 NJ | 0.188 | 
| Spain Junior |  ESP | DNF | 0.156 |