INNOVATIONS IN REHABILITATION

made to compare patellofemoral forces generated during forward and backward gait. Flynn (7) reported significantly lower peak knee extensor moments and peak patellofemoral compressive forces in back- ward versus forward running. Peak patellofemoral joint contact forces were 425.3N ± 129.2N for forward running and 222.7N ± 192N for backward running. Peak patellofemoral joint contact forces as a percentage of bodyweight were 5.6 ± 1.3 and 3.0 ± 0.6 for forward and backward running respectively. As a result of the decreased forces at the patellofemoral joint during backward walking as outlined above the use of backward walking has gained popularity over the last few years in the rehabilitation of a variety of knee injuries (12-13).

Anterior cruciate ligament rehabilitation Backward walking is commonly used in rehabilitation after ACL injury as co- contraction and strengthening of the quadriceps and hamstrings is a corner stone of post-ACL reconstruction rehabili- tation. The evidence to date clearly shows that muscle activity generally tends to be higher in backward walking gait than for- ward walking gait. The evidence suggests that the increase in hamstring activity during the initial contact to loading response phase of the gait cycle is not proportional to the increase in quadriceps activity. It is therefore unclear as to whether the hamstrings sufficiently count- eract this increase in quadriceps activity. This may be a limiting factor in utilising backward walking as an effective rehabili- tation exercise due to the possibility of an increase of anterior shear forces, which may disrupt the integrity of the anterior cruciate ligament. There are no studies to date that have determined the optimal activity needed in the hamstrings to coun- teract the increase in quadriceps activity and prevent anterior shear forces. Future studies are therefore needed to delineate the interactions between quadriceps and hamstring muscle exertions and cruciate ligament forces.

Maintenance of cardiovascular fitness As mentioned in the review of literature, backward walking provides a greater car- diopulmonary response than similar levels of exertion during forward walking. With the increased muscle activity and

22

decreased loading during backward walk- ing it is clear that in the early stages of rehabilitation backward walking may be useful in maintaining cardiovascular fit- ness at a time when the patient may be unable to run.

FUTURE RESEARCH Although the current research suggests there are many positive benefits to retro- grade ambulation further research is required to confirm current studies as rel- atively few have been carried out to date. One area that is of specific importance is comparing the forces in backward walking and forward walking at joints such as the ankle, knee and hip. This will give us a greater appreciation of the potential con- ditions in which BW could be effective and importantly at what stage.

Finally intervention studies using BW as all or part of treatment would be of benefit as to the authors’ knowledge no such studies exist. These could take place using patellofemoral pain syndrome, ACL recon- struction or even chronic lower back pain.

CONCLUSIONS In summary, the literature has highlighted that backward walking and running has been shown to be an effective rehabilita- tion exercise for a variety of knee disorders including patellofemoral pain. The consen- sus of the studies is that the walking pat- tern is kinematically similar but reversed during forward walking and backward walking. EMG activity generally tends to be higher in backward walking gait than for- ward walking gait. Vertical GRF’s are lower in backward running when compared to forward running and peak patello-femoral joint forces are less (3.0 x bodyweight) in backward running compared to (5.6 x bodyweight) in forward running. While fur- ther research is required, this article out- lines some of the potential benefits and uses that retrograde ambulation or back- wards walking offers in the rehabilitation of the injured patient.

THE AUTHORS Christian Poole, BSc (Hons), GSR is a lec- turer on the Sport Rehabilitation degree course at St Mary’s College. He is studying for an MSc in applied biomechanics. He is a practicing clinician with ten years experience working in sport and is currently a member of the BASRaT executive committee.

Michael Nicol, MSc, GSR, SRP is the reha- bilitation director at Sport Dimensions, Physiotherapy, Rehabilitation and Performance Centre, Chiswick, London. He is a graduate sport rehabilitator and com- pleted his MSc in sports medicine at Nottingham University. He has worked in elite hockey and rugby league.

References 1. Albensi RJ; Nyland J; Caborn D. The rela- tionship of body weight and clinical foot and ankle measurements to the heel forces of for- ward and backward walking. Journal of Athletic Training 1999;34(4): 328-333 2. Grasso R; Bianchi L and Lacquanti F. Motor patterns for human gait: Backward versus for- ward locomotion. Journal of Neurophysiology 1998;80:1868-1885 3. Thorstensson A. How is the normal locomo- tor programme modified to produce backward walking? Experimental Brain Research 1986;61:664-668 4. Winter DA and Pluck N. Backward walking: A simple reversal of forward walking? Journal of Motor Behaviour 1989;21(3): 291-305 5. Vilensky JA; Gankiewicz E and Gehlsen G. 1987. A kinematic comparison of backward and forward walking in humans. Journal of Human Movement Studies. 13: 29-50 6. Kramer JF and Reid DC. Backward walking. A cinematographic and electromyographic pilot study. Physiotherapy 1981; 33(2):77-86 7. Flynn TW and Soutas-Little R. Patellofemoral joint compressive forces in forward and back- ward running. Journal of Orthopaedic and sports Physical Therapy 1995;21(5):277- 281 8. Kraemer C. An electromyographic study of forward and backward walking in normals and in subjects following anterior cruciate ligament repair. Master of Physical Therapy Indep- endent Study. University of North Dakota 1998 9. Cipriani DJ; Armstrong C and Gaul S. 1995. Backward walking at three levels of treadmill inclination: An electromyographic and kinemat- ic analysis. Journal of Orthopaedic and sports Physical Therapy 1995;22(3):95-102 10. Threlkeld AJ; Horn TS; Wojitowicz GM; Rooney JG and Shapiro R. Kinematics, ground reaction force and muscle balance produced by backward running. Journal of Orthopaedic and sports Physical Therapy 1989;11(2):56-63 11. Chaloupka EC, Kang J, MA Mastrangelo and Donnelly MS. Cardiorespiratory and metabolic responses during forward and backward walk- ing. Journal of Orthopaedic Sports Physical Therapy 1997;25(5):302-306 12. Flynn TW, Connery SM, Smutok MA, Zeballos RJ and Weisman IM. Comparison of cardiopulmonary responses to forward and backward walking and running. Medicine and Science in Sports and Exercise 1994;26(1):89-94 13. Van Deursen RWM, Flynn TW, et al. Does a single control mechanism exist for both forward and backward walking? Gait and Posture 1998;7:214-224

www.sportex.net