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: Peak grip force in ON - state was 140 % ( P < 0 . 05 ) higher in Parkinson ' s disease + LID than in Parkinson ' s disease - LID , while static grip force was increased by 138 % ( P < 0 . 01 ) between groups .
### Output Text:
Peak grip force in ON - state was 140 % ( P < 0 . 05 ) higher in Parkinson ' s disease + LID than in Parkinson ' s disease - LID , while static grip force was increased by 138 % ( P < 0 . 01 ) between groups . 