diphenhydramine started at 6.25mg twice daily for 3 days; diphenhydramine increased to 12.5mg twice daily for 7 days; diphenhydramine reduced to 6.25mg twice daily for 3 days.

Subjects were instructed to walk on the treadmill and to tell the research coordinator to stop testing when they reached the point at which they typically would need to stop and sit down, or until 15 minutes had elapsed. When the subject reached their maximum distance, the treadmill testing was stopped. This was recorded as total distance based on number of minutes and seconds walked. Minutes was converted to meters based on calculation of defined speed of the treadmill.

After the subject completed the treadmill test they were asked to immediately return to the seated position. At this point a timer was started. When the subjects pain level returned to baseline (level of pain subject felt in a seated position before walking) the time was stopped. This was recorded as recovery time. Maximum recovery time is 15 minutes.

Subjects were instructed to walk on the treadmill and to tell the research coordinator to stop testing when they reached the point at which they typically would need to stop and sit down, or until 15 minutes had elapsed. At defined intervals (every 30 seconds) subjects were asked what their pain level was according to the NRS. The area under the curve of present pain intensity multiplied by the amount of time the subject walked.

The VAS asked subjects to place a mark indicative of their low back pain during the past day on a 100mm line, with 0mm representing no pain and 100mm representing extreme pain.

The ODI is a set of 10 questions each with five choices (maximum score of 5 points per question) designed to determine how back pain has affected the ability to manage everyday life (pain intensity, personal care, lifting, walking, sitting, standing, sleeping, social life, traveling, and change positions). A total score range of 0-50; score of 0 indicates no disability and a score of 50 would indicate 100% disability.

The SSS is a series of questions asking about symptom severity, physical function, and satisfaction. The symptom severity section is a set of 7 questions (maximum score is 5 points per question) and asks to rate pain for each question based on no pain, mild, moderate, severe or very severe pain. The total score (maximum=35) is added up and divided by seven. The maximum score for the symptom severity section (score=5) indicates very severe symptom severity.

The SSS is a series of questions asking about symptom severity, physical function, and satisfaction. The physical function section is a series of 5 questions (maximum 4 points per question) and asks to rate function for each question based on comfortably, sometimes with pain, always with pain, no functional ability. The total score (max=20) is divided by five. The maximum score for the physical function section (max=4) indicates no ability to function.

The mBPI is a series of questions that rates the severity and impact of pain on daily function. The questionnaire is made up of 4 pain severity items using the NRS scale, and seven pain interference sub-scales. The final interference score is an average of the seven sub-scales (0 indicating no interference and 10 indicating complete interference).

The RMDQ consists of 24 yes/no statements about activity limitations due to back pain. These questions center on movement, ambulation, and self-care activities. Positive (yes) answers each contribute 1 point to cumulative score with total scores ranging from 0 (no disability) to 24 (severely disabled).

Subjects were asked to rate their low back pain according to the PGA. PGA is the impact of disease activity. PGA was measured on a 5-point scale, where 1=very good, 2=good, 3=fair, 4=poor, and 5=very poor.

Subjects were instructed to walk on the treadmill and to tell the research coordinator to stop testing when they reached the point at which they typically would need to stop and sit down, or until 15 minutes had elapsed. At defined intervals subjects were asked what their pain level was according to the NRS. When the subject reached their maximum distance, they were asked their NRS score. This was recorded as final pain intensity. Using the Numeric Rating Scale (NRS) (0=no pain, 10=worst pain imaginable)the time to first symptoms (Tfirst) with a NRS score greater than or equal to 4 (moderate pain level), with treadmill ambulation was measured.

Outcome measures were obtained for all subjects as described in the Analysis Population Description of the primary outcome above.

Subjects were instructed to walk on the treadmill and to tell the research coordinator to stop testing when they reached the point at which they typically would need to stop and sit down, or until 15 minutes had elapsed. When the subject reached their maximum distance, the treadmill testing was stopped. This was recorded as total distance based on number of minutes and seconds walked. Minutes was converted to meters based on calculation of defined speed of the treadmill.

Outcome measures were obtained for all subjects as described in the Analysis Population Description of the primary outcome above.

After the subject completed the treadmill test they were asked to immediately return to the seated position. At this point a timer was started. When the subjects pain level returned to baseline (level of pain subject felt in a seated position before walking) the time was stopped. This was recorded as recovery time. Maximum recovery time is 15 minutes.

Outcome measures were obtained for all subjects as described in the Analysis Population Description of the primary outcome above.

Subjects were instructed to walk on the treadmill and to tell the research coordinator to stop testing when they reached the point at which they typically would need to stop and sit down, or until 15 minutes had elapsed. At defined intervals (every 30 seconds) subjects were asked what their pain level was according to the NRS. The area under the curve of present pain intensity multiplied by the amount of time the subject walked.

Outcome measures were obtained for all subjects as described in the Analysis Population Description of the primary outcome above.

The VAS asked subjects to place a mark indicative of their low back pain during the past day on a 100mm line, with 0mm representing no pain and 100mm representing extreme pain.

Outcome measures were obtained for all subjects as described in the Analysis Population Description of the primary outcome above.

The ODI is a set of 10 questions each with five choices (maximum score of 5 points per question) designed to determine how back pain has affected the ability to manage everyday life (pain intensity, personal care, lifting, walking, sitting, standing, sleeping, social life, traveling, and change positions). A total score range of 0-50; score of 0 indicates no disability and a score of 50 would indicate 100% disability.

Outcome measures were obtained for all subjects as described in the Analysis Population Description of the primary outcome above.

The SSS is a series of questions asking about symptom severity, physical function, and satisfaction. The symptom severity section is a set of 7 questions (maximum score is 5 points per question) and asks to rate pain for each question based on no pain, mild, moderate, severe or very severe pain. The total score (maximum=35) is added up and divided by seven. The maximum score for the symptom severity section (score=5) indicates very severe symptom severity.

Outcome measures were obtained for all subjects as described in the Analysis Population Description of the primary outcome above.

The SSS is a series of questions asking about symptom severity, physical function, and satisfaction. The physical function section is a series of 5 questions (maximum 4 points per question) and asks to rate function for each question based on comfortably, sometimes with pain, always with pain, no functional ability. The total score (max=20) is divided by five. The maximum score for the physical function section (max=4) indicates no ability to function.

Outcome measures were obtained for all subjects as described in the Analysis Population Description of the primary outcome above.

The mBPI is a series of questions that rates the severity and impact of pain on daily function. The questionnaire is made up of 4 pain severity items using the NRS scale, and seven pain interference sub-scales. The final interference score is an average of the seven sub-scales (0 indicating no interference and 10 indicating complete interference).

Outcome measures were obtained for all subjects as described in the Analysis Population Description of the primary outcome above.

The RMDQ consists of 24 yes/no statements about activity limitations due to back pain. These questions center on movement, ambulation, and self-care activities. Positive (yes) answers each contribute 1 point to cumulative score with total scores ranging from 0 (no disability) to 24 (severely disabled).

Outcome measures were obtained for all subjects as described in the Analysis Population Description of the primary outcome above.

Subjects were asked to rate their low back pain according to the PGA. PGA is the impact of disease activity. PGA was measured on a 5-point scale, where 1=very good, 2=good, 3=fair, 4=poor, and 5=very poor.

Outcome measures were obtained for all subjects as described in the Analysis Population Description of the primary outcome above.

Diphenhydramine started at 6.25mg twice daily for 3 days; diphenhydramine increased to 12.5mg twice daily for 7 days; diphenhydramine reduced to 6.25mg twice daily for 3 days.