Is it healthy to exercise a muscle when it's still sore?

Error message

• Notice: Trying to access array offset on value of type int in element_children() (line 6595 of H:\root\home\marcluo777-001\www\healthcentre\includes\common.inc).
• Notice: Trying to access array offset on value of type int in element_children() (line 6595 of H:\root\home\marcluo777-001\www\healthcentre\includes\common.inc).
• Notice: Trying to access array offset on value of type int in element_children() (line 6595 of H:\root\home\marcluo777-001\www\healthcentre\includes\common.inc).
• Notice: Trying to access array offset on value of type int in element_children() (line 6595 of H:\root\home\marcluo777-001\www\healthcentre\includes\common.inc).
• Notice: Trying to access array offset on value of type int in element_children() (line 6595 of H:\root\home\marcluo777-001\www\healthcentre\includes\common.inc).
• Notice: Trying to access array offset on value of type int in element_children() (line 6595 of H:\root\home\marcluo777-001\www\healthcentre\includes\common.inc).
• Notice: Trying to access array offset on value of type int in element_children() (line 6595 of H:\root\home\marcluo777-001\www\healthcentre\includes\common.inc).
• Notice: Trying to access array offset on value of type int in element_children() (line 6595 of H:\root\home\marcluo777-001\www\healthcentre\includes\common.inc).
• Notice: Trying to access array offset on value of type int in element_children() (line 6595 of H:\root\home\marcluo777-001\www\healthcentre\includes\common.inc).
• Notice: Trying to access array offset on value of type int in element_children() (line 6595 of H:\root\home\marcluo777-001\www\healthcentre\includes\common.inc).
• Notice: Trying to access array offset on value of type int in element_children() (line 6595 of H:\root\home\marcluo777-001\www\healthcentre\includes\common.inc).
• Notice: Trying to access array offset on value of type int in element_children() (line 6595 of H:\root\home\marcluo777-001\www\healthcentre\includes\common.inc).
• Notice: Trying to access array offset on value of type int in element_children() (line 6595 of H:\root\home\marcluo777-001\www\healthcentre\includes\common.inc).
• Deprecated function: implode(): Passing glue string after array is deprecated. Swap the parameters in drupal_get_feeds() (line 394 of H:\root\home\marcluo777-001\www\healthcentre\includes\common.inc).
• Deprecated function: The each() function is deprecated. This message will be suppressed on further calls in menu_set_active_trail() (line 2405 of H:\root\home\marcluo777-001\www\healthcentre\includes\menu.inc).