Jack-knife stretching promotes flexibility of tight hamstrings after 4 weeks: a pilot study

  • Koichi Sairyo
  • Takeshi Kawamura
  • Yasuyoshi Mase
  • Yasushi Hada
  • Toshinori Sakai
  • Kiyotaka Hasebe
  • Akira Dezawa
Original Article


Tight hamstrings are reported to be one of the causes of low back pain. However, there have been few reports on effective stretching procedures for the tight hamstrings. The so-called jack-knife stretch, an active-static type of stretching, can efficiently increase the flexibility of tight hamstrings. To evaluate hamstring tightness before and after the 4-week stretching protocol in healthy volunteer adults and patients aged under 18 years with low back pain. For understanding the hamstrings tightness, we measured two parameters including (1) finger to floor distance (FFD) and (2) pelvis forward inclination angle (PFIA). Eight healthy adult volunteers who had no lumbar or hip problems participated in this study (mean age: 26.8 years). All lacked flexibility and their FFD were positive before the experiment. Subjects performed 2 sets of the jack-knife stretch every day for 4 weeks. One set consisted of 5 repetitions, each held for 5 s. Before and during the 4-week experiment, the FFD and PFIA of toe-touching tests were measured weekly. For 17 of the sports players aged under 18, only FFD was measured. In adult volunteers, FFD was 14.1 ± 6.1 cm before the experiment and decreased to −8.1 ± 3.7 cm by the end of week 4, indicating a gain in flexibility of 22.2 cm. PFIA was 50.6 ± 8.2 before the experiment and 83.8 ± 5.8 degrees after. Before and after the experiment, the differences were significant (p < 0.05). For those aged under 18, FFD was 8.1 ± 8.0 and −9.6 ± 6.8, before and after the stretching, respectively. This difference was significant (p < 0.05). The jack-knife stretch is a useful active-static stretching technique to efficiently increase flexibility of tight hamstrings.


Stretch Low back pain Hamstrings Lumbar spine Conservative treatment 



The authors thank Mr. Ryota Kawada for his technical advice regarding the jack-knife stretch.

Conflict of interest

No funds were received in support of this study.


  1. 1.
    Iwamoto J, Abe H, Tsukimura Y, Wakano K (2004) Relationship between radiographic abnormalities of lumbar spine and incidence of low back pain in high school and college football players: a prospective study. Am J Sports Med 32:781–786PubMedCrossRefGoogle Scholar
  2. 2.
    Iwamoto J, Abe H, Tsukimura Y, Wakano K (2005) Relationship between radiographic abnormalities of lumbar spine and incidence of low back pain in high school rugby players: a prospective study. Scand J Med Sci Sports 15:163–168PubMedCrossRefGoogle Scholar
  3. 3.
    Sairyo K, Katoh S, Sakamaki T, Komatsubara S, Endo K, Yasui N (2003) Three successive stress fractures at the same level in an adolescent baseball player. Am J Sports Med 31:606–610PubMedGoogle Scholar
  4. 4.
    Feldman DE, Shrier I, Rossignol M, Abenhaim L (2001) Risk factors for the development of low back pain in adolescence. Am J Epidemiol 154:30–36PubMedCrossRefGoogle Scholar
  5. 5.
    Harreby M, Nygaard B, Jessen T, Larsen E, Storr-Paulsen A, Lindahl A et al (1999) Risk factors for low back pain in a cohort of 1389 Danish school children: an epidemiologic study. Eur Spine J 8:444–450PubMedCrossRefGoogle Scholar
  6. 6.
    Esola MA, McClure PW, Fitzgerald GK, Siegler S (1996) Analysis of lumbar spine and hip motion during forward bending in subjects with and without a history of low back pain. Spine (Phila Pa 1976) 21:71–78Google Scholar
  7. 7.
    Kottke FJ, Pauley DL, Ptak RA (1966) The rationale for prolonged stretching for correction of shortening of connective tissue. Arch Phys Med Rehabil 47:345–352PubMedGoogle Scholar
  8. 8.
    Mierau D, Cassidy JD, Yong-Hing K (1989) Low-back pain and straight leg raising in children and adolescents. Spine (Phila Pa 1976) 14:526–528Google Scholar
  9. 9.
    Davis DS, Ashby PE, McCale KL, McQuain JA, Wine JM (2005) The effectiveness of 3 stretching techniques on hamstring flexibility using consistent stretching parameters. J Strength Cond Res 19:27–32PubMedGoogle Scholar
  10. 10.
    White SG, Sahrmann SA (1994) A movement system balance approach to management of musculoskeletal pain. In: Grant R (ed) Physical therapy of the cervical and thoracic spine. Churchill Livingstone Inc, New York, pp 339–357Google Scholar
  11. 11.
    Meroni R, Cerri CG, Lanzarini C, Barindelli G, Morte GD, Gessaga V et al (2010) Comparison of active stretching technique and static stretching technique on hamstring flexibility. Clin J Sport Med 20:8–14PubMedCrossRefGoogle Scholar
  12. 12.
    Lariviere C, Gagnon D, Loisel P (2000) The effect of load on the coordination of the trunk for subjects with and without chronic low back pain during flexion-extension and lateral bending tasks. Clin Biomech 15:407–416CrossRefGoogle Scholar
  13. 13.
    Sjolie AN (2004) Low-back pain in adolescents is associated with poor hip mobility and high body mass index. Scand J Med Sci Sports 14:168–175PubMedCrossRefGoogle Scholar
  14. 14.
    Fasen JM, O’Connor AM, Schwartz SL, Watson JO, Plastaras CT, Garvan CW, Bulcao C, Johnson SC, Akuthota V (2009) A randomized controlled trial of hamstring stretching: comparison of four techniques. J Strength Cond Res 23(2):660–667PubMedCrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2012

Authors and Affiliations

  • Koichi Sairyo
    • 1
  • Takeshi Kawamura
    • 2
  • Yasuyoshi Mase
    • 3
  • Yasushi Hada
    • 4
  • Toshinori Sakai
    • 5
  • Kiyotaka Hasebe
    • 4
  • Akira Dezawa
    • 1
  1. 1.Department of Orthopedic SurgeryTeikyo University Mizonokuchi HospitalTakatsu-kuJapan
  2. 2.Department of RehabilitationInayama HospitalTokushimaJapan
  3. 3.Hachioji Sports ClinicTokyoJapan
  4. 4.Department of Rehabilitation MedicineTeikyo University Mizonokuchi HospitalKawasakiJapan
  5. 5.Department of Orthopaedic SurgeryThe University of TokushimaTokushimaJapan

Personalised recommendations