Sean N. Martin, DO

Evidence summary

The Healthy People 2010 report calls for increasing the proportion of Americans who engage in moderate physical activity (activities that use large muscle groups and are at least equivalent to brisk walking) from 15% to 30%.¹ The report doesn’t describe how best to achieve this objective.

Systematic review reveals approaches worth trying
The US Department of Health and Human Services (DHHS) and the Centers for Disease Control and Prevention (CDC) conducted a systematic review of 94 qualifying trials and assigned interventions to 1 of 3 approaches: “information based,” “behavioral and social,” and “facilities and activities.”²

Behavioral and social interventions have the best data support.² Within this category, strong evidence backed school-based physical education and accountability partners or exercise support groups. School-based physical education resulted in a median net increase in physical activity time of 50.3% (range 6.0%-125.3%); accountability partners or support groups produced a mean net increase of 44.2% (interquartile range 19.9%-45.6%).

“Green” prescriptions are primary care behavioral interventions that include measurable goals, self-reward, structured problem-solving, social network reinforcement, and relapse prevention counseling. In the DHHS review, 10 trials studied green prescriptions; the median net increase in physical activity time was 35.4% (interquartile range 16.7%-83.3%).² A trial in 42 rural and urban New Zealand general practices that added 3 telephone follow-up sessions to the green prescription showed a 10% increase in achieving 150 minutes of vigorous exercise weekly among green prescription participants compared with controls (number needed to treat=10).³

Pedometers. A systematic review using meta-regression to calculate summary effects evaluated the use of pedometers by study participants for an average of 18 weeks.⁴ Pedometer users increased their physical activity significantly, by 2491 steps per day compared with controls (95% confidence interval [CI], 1098-3885 steps per day).⁴ In adults, walking normally and walking briskly for an average of 2500 steps burns 100 and 150 kcal, respectively.⁵

Here’s what works with kids
A British systematic review of 24 high-quality controlled trials involving adolescents and children reported significant improvements with interventions that were school-based and either community- or family-based. Multidimensional outcomes included a 42% increase in participation in regular physical activity and an increase of 83 minutes weekly in moderate-to-vigorous physical activity.⁶

A US meta-analysis of 11 after-school programs with an average contact time of 275 minutes per week showed a positive standardized mean difference effect size for physical activity (0.44; 95% CI, 0.28-0.60).⁷

Evidence for other interventions is lacking
Insufficient evidence exists to support other interventions, such as classroom-based informational health education, mass media campaigns, college-based health and physical education, and classroom-based education focused on reducing television viewing and video-game playing.²

Recommendations

The British National Institute for Health and Clinical Excellence (NICE) has found sufficient evidence to recommend brief interventions in primary care. They include:

• using a validated tool to identify inactive patients
• recommending at least 30 minutes of patient-specific exercise at least 5 days per week
• establishing exercise goals
• presenting patients with written material on the benefits of exercise and local exercise opportunities
• following up several times over a 3-to 6-month period.⁸

Acknowledgments
The opinions and assertions contained herein are the private views of the authors and not to be construed as official, or as reflecting the views of the US Air Force Medical Service or the US Air Force at large.

Evidence summary

The Healthy People 2010 report calls for increasing the proportion of Americans who engage in moderate physical activity (activities that use large muscle groups and are at least equivalent to brisk walking) from 15% to 30%.¹ The report doesn’t describe how best to achieve this objective.

Systematic review reveals approaches worth trying
The US Department of Health and Human Services (DHHS) and the Centers for Disease Control and Prevention (CDC) conducted a systematic review of 94 qualifying trials and assigned interventions to 1 of 3 approaches: “information based,” “behavioral and social,” and “facilities and activities.”²

Behavioral and social interventions have the best data support.² Within this category, strong evidence backed school-based physical education and accountability partners or exercise support groups. School-based physical education resulted in a median net increase in physical activity time of 50.3% (range 6.0%-125.3%); accountability partners or support groups produced a mean net increase of 44.2% (interquartile range 19.9%-45.6%).

“Green” prescriptions are primary care behavioral interventions that include measurable goals, self-reward, structured problem-solving, social network reinforcement, and relapse prevention counseling. In the DHHS review, 10 trials studied green prescriptions; the median net increase in physical activity time was 35.4% (interquartile range 16.7%-83.3%).² A trial in 42 rural and urban New Zealand general practices that added 3 telephone follow-up sessions to the green prescription showed a 10% increase in achieving 150 minutes of vigorous exercise weekly among green prescription participants compared with controls (number needed to treat=10).³

Pedometers. A systematic review using meta-regression to calculate summary effects evaluated the use of pedometers by study participants for an average of 18 weeks.⁴ Pedometer users increased their physical activity significantly, by 2491 steps per day compared with controls (95% confidence interval [CI], 1098-3885 steps per day).⁴ In adults, walking normally and walking briskly for an average of 2500 steps burns 100 and 150 kcal, respectively.⁵

Here’s what works with kids
A British systematic review of 24 high-quality controlled trials involving adolescents and children reported significant improvements with interventions that were school-based and either community- or family-based. Multidimensional outcomes included a 42% increase in participation in regular physical activity and an increase of 83 minutes weekly in moderate-to-vigorous physical activity.⁶

A US meta-analysis of 11 after-school programs with an average contact time of 275 minutes per week showed a positive standardized mean difference effect size for physical activity (0.44; 95% CI, 0.28-0.60).⁷

Evidence for other interventions is lacking
Insufficient evidence exists to support other interventions, such as classroom-based informational health education, mass media campaigns, college-based health and physical education, and classroom-based education focused on reducing television viewing and video-game playing.²

Recommendations

The British National Institute for Health and Clinical Excellence (NICE) has found sufficient evidence to recommend brief interventions in primary care. They include:

• using a validated tool to identify inactive patients
• recommending at least 30 minutes of patient-specific exercise at least 5 days per week
• establishing exercise goals
• presenting patients with written material on the benefits of exercise and local exercise opportunities
• following up several times over a 3-to 6-month period.⁸

Acknowledgments
The opinions and assertions contained herein are the private views of the authors and not to be construed as official, or as reflecting the views of the US Air Force Medical Service or the US Air Force at large.

Evidence summary

The Healthy People 2010 report calls for increasing the proportion of Americans who engage in moderate physical activity (activities that use large muscle groups and are at least equivalent to brisk walking) from 15% to 30%.¹ The report doesn’t describe how best to achieve this objective.

Systematic review reveals approaches worth trying
The US Department of Health and Human Services (DHHS) and the Centers for Disease Control and Prevention (CDC) conducted a systematic review of 94 qualifying trials and assigned interventions to 1 of 3 approaches: “information based,” “behavioral and social,” and “facilities and activities.”²

Behavioral and social interventions have the best data support.² Within this category, strong evidence backed school-based physical education and accountability partners or exercise support groups. School-based physical education resulted in a median net increase in physical activity time of 50.3% (range 6.0%-125.3%); accountability partners or support groups produced a mean net increase of 44.2% (interquartile range 19.9%-45.6%).

“Green” prescriptions are primary care behavioral interventions that include measurable goals, self-reward, structured problem-solving, social network reinforcement, and relapse prevention counseling. In the DHHS review, 10 trials studied green prescriptions; the median net increase in physical activity time was 35.4% (interquartile range 16.7%-83.3%).² A trial in 42 rural and urban New Zealand general practices that added 3 telephone follow-up sessions to the green prescription showed a 10% increase in achieving 150 minutes of vigorous exercise weekly among green prescription participants compared with controls (number needed to treat=10).³

Pedometers. A systematic review using meta-regression to calculate summary effects evaluated the use of pedometers by study participants for an average of 18 weeks.⁴ Pedometer users increased their physical activity significantly, by 2491 steps per day compared with controls (95% confidence interval [CI], 1098-3885 steps per day).⁴ In adults, walking normally and walking briskly for an average of 2500 steps burns 100 and 150 kcal, respectively.⁵

Here’s what works with kids
A British systematic review of 24 high-quality controlled trials involving adolescents and children reported significant improvements with interventions that were school-based and either community- or family-based. Multidimensional outcomes included a 42% increase in participation in regular physical activity and an increase of 83 minutes weekly in moderate-to-vigorous physical activity.⁶

A US meta-analysis of 11 after-school programs with an average contact time of 275 minutes per week showed a positive standardized mean difference effect size for physical activity (0.44; 95% CI, 0.28-0.60).⁷

Evidence for other interventions is lacking
Insufficient evidence exists to support other interventions, such as classroom-based informational health education, mass media campaigns, college-based health and physical education, and classroom-based education focused on reducing television viewing and video-game playing.²

Recommendations

The British National Institute for Health and Clinical Excellence (NICE) has found sufficient evidence to recommend brief interventions in primary care. They include:

• using a validated tool to identify inactive patients
• recommending at least 30 minutes of patient-specific exercise at least 5 days per week
• establishing exercise goals
• presenting patients with written material on the benefits of exercise and local exercise opportunities
• following up several times over a 3-to 6-month period.⁸

Acknowledgments
The opinions and assertions contained herein are the private views of the authors and not to be construed as official, or as reflecting the views of the US Air Force Medical Service or the US Air Force at large.

Evidence summary

A comprehensive review of the literature revealed no studies that compare heat and cryotherapy to treat acute soft-tissue injury. Well-designed human trials of general management of acute soft-tissue injury are rare.¹

Cryotherapy has been the recommended initial treatment for muscle strain for more than 30 years, based generally on expert opinion and physiological models, not clinical trials.² Theoretically, cryotherapy controls hemorrhage and tissue edema, whereas heat enhances the inflammatory response.²

One human RCT and animal studies find benefits from cold

A 2007 review evaluated 66 publications and found only 1 randomized controlled trial conducted on humans.³ The intervention in this trial involved applying cold gel 4 times a day for the first 14 days after the injury. The control group received a room-temperature gel application; neither group was aware of the temperature differential.

The study found significant reduction in pain at rest, pain with movement, and functional disability at intervals of 7, 14, and 28 days postinjury (P<.001) among patients receiving cold-gel applications. Patients receiving cold-gel treatment also reported increased satisfaction with treatment compared with the controls. At 28 days, cold-gel treatment patients scored 71 on a 100-point satisfaction scale compared with 44 for controls (P<.001).³ Inconclusive results or significant design flaws limited the validity of all other trials cited in this review.³

Laboratory studies on rats have also demonstrated beneficial effects of cryotherapy after simulated soft-tissue injuries.^4,5 One study cited a significant reduction in inflammatory cells, based on histologic examination, in 43 rats between 6 and 24 hours after trauma.⁴ A second study of 21 rats showed improvement in associated physiological components with cryotherapy, but no statistically significant improvement in edema.⁵

How cold is too cold?

Most authorities recommend empiric treatment with cryotherapy during the acute inflammatory phase—the first 24 to 48 hours after injury.⁶ Although not rigorously studied, some sources recommend applying cold to the involved muscle for the first 4 hours after injury at intervals of 10 to 20 minutes every 30 to 60 minutes.⁶

The literature focuses more on the optimal temperature for cryotherapy than on the duration and frequency of therapy.⁷ Temperatures below 15°to 25°C may actually result in vasodilatation rather than vasoconstriction.⁷

Evidence for heat is limited

A 2006 Cochrane review that addressed treatment of lower back muscular strain, not soft-tissue injuries in general, found moderate evidence that heat therapy reduces pain by 17% and disability in the acute setting (P=.001).⁸ The review also cited 2 head-to-head trials that compared heat and cryotherapy; however, the study designs were poor and the results were contradictory.⁸

Recommendations

Authoritative textbooks consistently recommend applying ice for initial treatment of musculoskeletal and soft-tissue strains.⁹

Acknowledgments

The opinions and assertions contained herein are the private views of the authors and not to be construed as official or as reflecting the views of the United States Air Force Medical Service or the United States Air Force at large.

Evidence summary

A comprehensive review of the literature revealed no studies that compare heat and cryotherapy to treat acute soft-tissue injury. Well-designed human trials of general management of acute soft-tissue injury are rare.¹

Cryotherapy has been the recommended initial treatment for muscle strain for more than 30 years, based generally on expert opinion and physiological models, not clinical trials.² Theoretically, cryotherapy controls hemorrhage and tissue edema, whereas heat enhances the inflammatory response.²

One human RCT and animal studies find benefits from cold

A 2007 review evaluated 66 publications and found only 1 randomized controlled trial conducted on humans.³ The intervention in this trial involved applying cold gel 4 times a day for the first 14 days after the injury. The control group received a room-temperature gel application; neither group was aware of the temperature differential.

The study found significant reduction in pain at rest, pain with movement, and functional disability at intervals of 7, 14, and 28 days postinjury (P<.001) among patients receiving cold-gel applications. Patients receiving cold-gel treatment also reported increased satisfaction with treatment compared with the controls. At 28 days, cold-gel treatment patients scored 71 on a 100-point satisfaction scale compared with 44 for controls (P<.001).³ Inconclusive results or significant design flaws limited the validity of all other trials cited in this review.³

Laboratory studies on rats have also demonstrated beneficial effects of cryotherapy after simulated soft-tissue injuries.^4,5 One study cited a significant reduction in inflammatory cells, based on histologic examination, in 43 rats between 6 and 24 hours after trauma.⁴ A second study of 21 rats showed improvement in associated physiological components with cryotherapy, but no statistically significant improvement in edema.⁵

How cold is too cold?

Most authorities recommend empiric treatment with cryotherapy during the acute inflammatory phase—the first 24 to 48 hours after injury.⁶ Although not rigorously studied, some sources recommend applying cold to the involved muscle for the first 4 hours after injury at intervals of 10 to 20 minutes every 30 to 60 minutes.⁶

The literature focuses more on the optimal temperature for cryotherapy than on the duration and frequency of therapy.⁷ Temperatures below 15°to 25°C may actually result in vasodilatation rather than vasoconstriction.⁷

Evidence for heat is limited

A 2006 Cochrane review that addressed treatment of lower back muscular strain, not soft-tissue injuries in general, found moderate evidence that heat therapy reduces pain by 17% and disability in the acute setting (P=.001).⁸ The review also cited 2 head-to-head trials that compared heat and cryotherapy; however, the study designs were poor and the results were contradictory.⁸

Recommendations

Authoritative textbooks consistently recommend applying ice for initial treatment of musculoskeletal and soft-tissue strains.⁹

Acknowledgments

The opinions and assertions contained herein are the private views of the authors and not to be construed as official or as reflecting the views of the United States Air Force Medical Service or the United States Air Force at large.

Evidence summary

A comprehensive review of the literature revealed no studies that compare heat and cryotherapy to treat acute soft-tissue injury. Well-designed human trials of general management of acute soft-tissue injury are rare.¹

Cryotherapy has been the recommended initial treatment for muscle strain for more than 30 years, based generally on expert opinion and physiological models, not clinical trials.² Theoretically, cryotherapy controls hemorrhage and tissue edema, whereas heat enhances the inflammatory response.²

One human RCT and animal studies find benefits from cold

A 2007 review evaluated 66 publications and found only 1 randomized controlled trial conducted on humans.³ The intervention in this trial involved applying cold gel 4 times a day for the first 14 days after the injury. The control group received a room-temperature gel application; neither group was aware of the temperature differential.

The study found significant reduction in pain at rest, pain with movement, and functional disability at intervals of 7, 14, and 28 days postinjury (P<.001) among patients receiving cold-gel applications. Patients receiving cold-gel treatment also reported increased satisfaction with treatment compared with the controls. At 28 days, cold-gel treatment patients scored 71 on a 100-point satisfaction scale compared with 44 for controls (P<.001).³ Inconclusive results or significant design flaws limited the validity of all other trials cited in this review.³

Laboratory studies on rats have also demonstrated beneficial effects of cryotherapy after simulated soft-tissue injuries.^4,5 One study cited a significant reduction in inflammatory cells, based on histologic examination, in 43 rats between 6 and 24 hours after trauma.⁴ A second study of 21 rats showed improvement in associated physiological components with cryotherapy, but no statistically significant improvement in edema.⁵

How cold is too cold?

Most authorities recommend empiric treatment with cryotherapy during the acute inflammatory phase—the first 24 to 48 hours after injury.⁶ Although not rigorously studied, some sources recommend applying cold to the involved muscle for the first 4 hours after injury at intervals of 10 to 20 minutes every 30 to 60 minutes.⁶

The literature focuses more on the optimal temperature for cryotherapy than on the duration and frequency of therapy.⁷ Temperatures below 15°to 25°C may actually result in vasodilatation rather than vasoconstriction.⁷

Evidence for heat is limited

A 2006 Cochrane review that addressed treatment of lower back muscular strain, not soft-tissue injuries in general, found moderate evidence that heat therapy reduces pain by 17% and disability in the acute setting (P=.001).⁸ The review also cited 2 head-to-head trials that compared heat and cryotherapy; however, the study designs were poor and the results were contradictory.⁸

Recommendations

Authoritative textbooks consistently recommend applying ice for initial treatment of musculoskeletal and soft-tissue strains.⁹

Acknowledgments

The opinions and assertions contained herein are the private views of the authors and not to be construed as official or as reflecting the views of the United States Air Force Medical Service or the United States Air Force at large.