scientific evidence

  • For Leg Strength and Power

    • A study published in the Journals of Gerontology looked at the influence of leg power and hip and knee strength regarding functional mobility in community-dwelling older adults. The study concluded that all factors were indeed significantly associated with the participants’ ability to perform activities vital to functional independence, with leg power being the most significant.

    • A 2005 study in the Journals of Gerontology utilized a chair rise test to assess functional leg power. This test was done by using a stopwatch to measure the minimum time taken to rise from a sitting to a standing position and then back down again 10 times. The results of this study indicated that these times, and therefore, leg power was significantly worse in participants with markers of poor health, such as musculoskeletal pain, hand osteoarthritis, and disabling/life-threatening health conditions such as diabetes, cancer, epilepsy, and cardiovascular disease. More notably, participants who did not have the physical ability to complete the chair rise test displayed even worse health markers than those with poor test times, indicating a direct relationship between this ability and long-term health.

    • Adams and colleagues divided subjects into a heavy squat group, a plyometric group (utilizing various squat patterns), or a combination squat-plyometric group. They compared them all to a control group that did not receive any intervention. The authors found significantly improved vertical jump measures for all test groups compared to the control group, with the combination group demonstrating the most significant improvement. These results indicate a clear relationship between training various squat patterns, in both a heavy resistance and plyometric fashion, for improvement in hip and thigh power production.

    • A study published in the Journal of Strength and Conditioning Research looked at strength and power predictors of speed in elite rugby players. The authors looked at measures of strength and power such as a 3RM (repetition maximum) high bar back squat, jump squat power output, countermovement jump height, drop jump height, isokinetic hamstring and quadricep peak torque, and 5-meter, 10-meter, and 30-meter sprint times. Once the results were calculated, the authors found that the 3RM squat load, squat jump power output, and counter jump height were the only measures found to be significantly greater in faster players. Again, these results clearly point to the superior effectiveness of using versions of the squat pattern to build longevity-producing strength, power, and speed.

    • Chelly and colleagues looked at the effect of a progressive resistance back squat regimen for improving leg power, jump, and sprint performance. All outcomes were found to be significantly improved after completion of the program; another example of the robust relationship between squatting and leg strength/power.

    REFERENCES:

    • Bean, J. F., Leveille, S. G., Kiely, D. K., Bandinelli, S., Guralnik, J. M., & Ferrucci, L. (2003). A Comparison of Leg Power and Leg Strength Within the InCHIANTI Study: Which Influences Mobility More? The Journals of Gerontology Series A: Biological Sciences and Medical Sciences, 58(8). doi:10.1093/gerona/58.8.m728

    • Kuh, D., Bassey, E. J., Butterworth, S., Hardy, R., & Wadsworth, M. E. (2005). Grip Strength, Postural Control, and Functional Leg Power in a Representative Cohort of British Men and Women: Associations With Physical Activity, Health Status, and Socioeconomic Conditions. The Journals of Gerontology Series A: Biological Sciences and Medical Sciences, 60(2), 224-231. doi:10.1093/gerona/60.2.224

    • Adams, K., Oshea, J. P., Oshea, K. L., & Climstein, M. (1992). The Effect of Six Weeks of Squat, Plyometric, and Squat-Plyometric Training on Power Production. The Journal of Strength and Conditioning Research, 6(1), 36. doi:10.1519/1533-4287(1992)0062.3.co;2

    • Cronin, J. B., & Hansen, K.T. (2005). Strength and Power Predictors of Sports Speed. The Journal of Strength and Conditioning Research, 19(2), 349. doi:10.1519/14323.1

    • Chelly, M. S., Fathloun, M., Cherif, N., Amar, M. B., Tabka, Z., & Praagh, E.V. (2009). Effects of a Back Squat Training Program on Leg Power, Jump, and Sprint Performances in Junior Soccer Players. Journal of Strength and Conditioning Research, 23(8), 2241-2249. doi:10.1519/jsc.0b013e3181b86c40

  • Fall and Frailty Prevention

    • Decreasing Impact Severity

      • In a study by Robinovitch, Brumer, and Maurer in the Journal of Biomechanics, the authors conducted backward falling experiments with young women from various inclined positions to assess the impact velocity of the falls. Once the results of this study were calculated, it was clear that squatting during the descent significantly decreased impact severity and that the earlier the squat response was initiated, the better. These results indicate that in order to protect ourselves from the possible damaging effects of falling, it is not only essential to attain a deep squat but also important to attain it at high speeds and under variable conditions.

      REFERENCE:

      • Robinovitch, S. N., Brumer, R., & Maurer, J. (2004). Effect of the “squat protective response” on impact velocity during backward falls. Journal of Biomechanics, 37(9), 1329- 1337. doi:10.1016/j.jbiomech.2003.12.015

    • ABILITY TO RISE FROM A SEAT

      • The CDC’s STEADI (Stopping, Elderly Accidents, Deaths, and Injuries) Initiative for healthcare providers utilizes the 30-second chair rise test and timed up-and-go test (TUG) to assess fall risk. The 30-second chair rise test consists of having an individual stand up and sit down as many times in 30 seconds as possible. The TUG test asks an individual to stand up, walk 10 feet and back, and then return to sitting in as short a time as possible. This assessment combines the movement skills of getting up from a chair and ambulation speed and measures general functional mobility. Below-average scores for the 30-second chair rise test are listed below, with these values indicating an increased risk of falling. For the TUG test, a time of greater or equal to 12 seconds would leave us at greater risk.

        • Chair Stand Score Cut-Offs for Fall Risk 

          • Age 60-64

            • Men: < 14

            • Women: < 12

          • Age 65-69

            • Men: < 12

            • Women: < 11

          • Age 70-74

            • Men: < 12

            • Women: < 10

          • Age 75-79

            • Men: < 11

            • Women: < 10

          • Age 80-84

            • Men: < 10

            • Women: < 9

          • Age 85-89

            • Men: < 8

            • Women: < 8

          • Age 90-94

            • Men: < 7

            • Women: < 4

          REFERENCE:

          • STEADI - Older Adult Fall Prevention. (2017, March 24). Retrieved from https://www. cdc.gov/steadi/materials.html

  • toileting and gastrointestinal health

    • A classic study by Taggart in 1966, found the anorectal angle straightens out as the hip joints are flexed as during a deep squat position. This straightening effect, along with a simultaneous opening of the anal canal, results in lessening the resistance at the anorectal junction, which increases the ease of defecation.

    • A study by Sirikov in 1987 looked at the effect of the deep squatting position on hemorrhoid development. In this study, the author advised hemorrhoid sufferers to wait for a strong need to defecate and then utilize a deep squatting position when doing so. After a year of heeding this advice, 90% of participants reported a significant reduction or complete absence of symptoms and reported no recurrences after a three-year follow-up.

    • In 2003, Sirikov followed up his study with another involving twenty-eight volunteers (ages 17-66 years) with normal bowel function. He used a digital timer to record the time needed for satisfactory emptying while defecating in one of three positions: sitting on a standard-sized toilet seat (41-42 cm high), sitting on a lower toilet seat (31-32 cm high), and deep squatting. After the results were calculated, it was concluded that deep squatting allowed for significantly less effort to reach the point of satisfactory emptying as compared to the other two positions.

      • This information by itself may not seem to have much bearing on our longevity; however, if we combine it with research demonstrating that infrequent and irregular bowel movements lead to a significantly increased risk of colorectal cancer, we can logically infer that any position that makes it easier for us to have bowel movements might just decrease our chances of irregularity, and therefore, reduce our risk of life-taking cancer.

    REFERENCES:

    • Tagart, R. E. (1966). The anal canal and rectum. Diseases of the Colon & Rectum, 9(6), 449-452. doi:10.1007/bf02617443

    • Sikirov BA. Management of Hemorrhoids: A New Approach, Israel Journal of Medical Sciences, 1987: 23, 284-286.

    • Sikirov, D. (2003, July). Comparison of straining during defecation in three positions: Results and implications for human health. Retrieved from https://www.ncbi.nlm.nih. gov/pubmed/12870773

    • Kojima, M., Wakai, K., Tokudome, S., Tamakoshi, K., Toyoshima, H., Watanabe, Y., . . . Tamakoshi, A. (2004). Bowel movement frequency and risk of colorectal cancer in a large cohort study of Japanese men and women. British Journal of Cancer, 90(7), 1397-1401. doi:10.1038/sj.bjc.6601735