In the sentence extracted from biomedical literature, identify all the chemical entities. The required answer format is the same sentence with HTML <span> tags to mark up specific entities. 
### Entity Markup Guides:
Use <span class="chemical"> to denote a chemical.

### Input Text: An overshooting of peak grip force by 51 % ( P < 0 . 05 ) and of static grip force by 45 % ( P < 0 . 01 ) was observed in the ON - compared with the OFF - drug condition .
### Output Text:
An overshooting of peak grip force by 51 % ( P < 0 . 05 ) and of static grip force by 45 % ( P < 0 . 01 ) was observed in the ON - compared with the OFF - drug condition . 