The percentage of number of waits to gain a lock on the MyISAM table versus the number of locks requested. MySQL uses table-level locking for MyISAM, MEMORY, and MERGE tables. The monitor threshold is analyzed against an average of values returned in polls to the agent where the Number of Samples parameter controls the number of samples included in the calculation of the average.
An unhealthy state indicates the percentage of table lock contention is high. The amount of waits required before a table lock is granted is too high.
To address high table lock contention percent try the possible options:
Use InnoDB as main table storage engine, which only uses row level locking
Insert rows into a temporary table temp_table and then update the real table periodically