**EXHIBIT 31.2****CERTIFICATION**I, Michael R. Robinson, Executive Vice President and Chief Financial Officer, certify that:     1. I have reviewed this quarterly report on Form 10-Q of Life Time Fitness, Inc.;     2. Based on my knowledge, this report does not contain any untrue statement of a material factor omit to state a material fact necessary to make the statements made, in light of thecircumstances under which such statements were made, not misleading with respect to the periodcovered by this report;     3. Based on my knowledge, the financial statements, and other financial information includedin this report, fairly present in all material respects the financial condition, results ofoperations and cash flows of the Company as of, and for, the periods presented in this report;     4. The Company’s other certifying officer and I are responsible for establishing andmaintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules13a-15(f) and 15d-15(f)) for the Company and we have:     a) designed such disclosure controls and procedures, or caused such disclosure controls andprocedures to be designed under our supervision, to ensure that material information relating tothe Company, including its consolidated subsidiaries, is made known to us by others within thoseentities, particularly during the period in which this report is being prepared;     b) designed such internal control over financial reporting, or caused such internal controlover financial reporting to be designed under our supervision, to provide reasonable assuranceregarding the reliability of financial reporting and the preparation of financial statements forexternal purposes in accordance with generally accepted accounting principles;     c) evaluated the effectiveness of the Company’s disclosure controls and procedures andpresented in this report our conclusions about the effectiveness of the disclosure controls andprocedures, as of the end of the period covered by this report based on such evaluation; and     d) disclosed in this report any change in the Company’s internal control over financialreporting that occurred during the Company’s most recent fiscal quarter (the Company’s fourthfiscal quarter in the case of an annual report) that has materially affected, or is reasonablylikely to materially affect, the Company’s internal control over financial reporting; and     5. The Company’s other certifying officer and I have disclosed, based on our most recentevaluation of internal control over financial reporting, to the Company’s auditors and the auditcommittee of the Company’s board of directors (or persons performing the equivalent functions):     a) all significant deficiencies and material weaknesses in the design or operation ofinternal control over financial reporting which are reasonably likely to adversely affect theCompany’s ability to record, process, summarize and report financial information; and     b) any fraud, whether or not material, that involves management or other employees who havea significant role in the Company’s internal control over financial reporting.Date: November 2, 2006              /s/ Michael R. Robinson   Michael R. Robinson   *Executive Vice President and Chief Financial Officer*