A Comparative Study of Effect of Forward vs Backward Walking on Quadriceps Strength Among College Students in Banglore

Introduction

Backward walking is a form of exercise that has been introduced as a method for gait performance improvement. Backward walking is seen to share similarities with forward walking but also has its distinctive features. While walking backward, people need to depend more on the auditory and sensory systems rather than the visual system as they do not have a complete view of the environment ahead.¹ Backward walking is an activity that has joint kinematic patterns different from forward walking. When walking backward, the leg does not only reverse its direction of movement but also travels in the opposite direction along the same path as in walking forward.² Stance starts at the heel strike and ends at the toe-off during forward walking, whereas it begins with the contact of the toes on the floor and finishes as the heel is lifted during backward walking. Hence, backward walking leads to modification of the biomechanical constraint and may help to get insight into the control of human locomotion.³ Although it may appear unlikely, training individuals to walk backward has been used as a means of improving gait and mobility.⁴ In addition, a large increase in the activity of knee extensors during backward walking can be useful for strengthening the quadriceps.⁵ Backward walking causes the isometric and concentric activity of the quadriceps’ femoris muscle, while the muscle activity during forward walking is mainly eccentric. Backward walking is the activity that results in a joint kinematic pattern different from forward walking.⁶ Performance of quadriceps and hamstring muscle is important for ambulation as the activation of the quadriceps immediately after the initial contact can reduce the energy needed for heel strike and hamstring muscle activated during the swing phase of the gait cycle to flex the knee joint.⁷ Forward walking and backward walking are the most commonly used closed-chain exercises.⁸ Backward walking is an emerging exercise that helps to increase the muscle strength of the lower limb. Forward walking and backward walking have been compared in previous studies for many aspects including kinematics and kinetics, elevation angle, and muscle activity. But the effect of backward walking on quadriceps strength has not been studied objectively. Thus, the present study aims to see the effect of backward and forward walking on quadriceps strength and compare it.

Methodology

The data for the study was taken from the Padmashree Institute of Physiotherapy in Bangalore. This clinical trial was conducted for 6 months (September 2021– February 2022). A total of 30 students both male and female (15 in each group) of age group 18–30 years studying at the study center were included in the study. All the participants included were comfortable with backward walking. Subjects with any surgery of the hip, knee, or ankle joint involving ligament and meniscus in the last six months and who were participating in any exercise regularly were excluded.

Backward walking (BW) training protocol- Initially, each subject was made to walk 10 steps forward and 9 steps backward and was observed for any discomfort. If no discomfort was observed, the patient was made to walk backward for 10 mins per session barefoot without any auditory or visual feedback. This was followed by unilateral straight leg raise, hamstring stretching, and static quadriceps exercises. This training program was carried out for 20 mins for 3 days per week for 4 weeks with a total of 12 sessions.

Forward walking (FW) training protocol: The patient was made to walk forward barefoot freely at different speeds, chosen for 10 minutes per session. This was followed by unilateral straight leg raise, hamstring stretching, and static quadriceps exercises. This training program was also carried out for 20 minutes for 3 days per week for 4 weeks with a total of 12 sessions.

Participants of both groups were made to walk on the same surface without prior training for the backward training group (Figure 1).

Quadriceps strength was tested by a Micro FET2 dynamometer by asking the participant to sit on the couch by placing the hip and knee at 90°- 90°. Micro FET2 dynamometer was positioned just above the malleoli and the participant was asked to do an isometric contraction of the quadriceps and strength was measured. The measurement was repeated 3 times and an average of the 3 values was taken for final consideration.

Results

The results were analyzed using the statistical software SPSS 21.0 version. Both descriptive and inferential analyses were used. Both parametric and non-parametric tests were used suitably. MS-EXCEL, MS-WORD, and SPSS graphical editors were used to generate the tables.

According to table 1, a similar proportion of subjects were found among college students based on gender, but it was not statistically significant (x2=1.429, df=1) at the 5% level, i.e., p>0.005. It is evidenced that the baseline characteristic of gender is homogenous in both groups.

Table 2 presents the outcomes of the baseline variables of college students in both groups. The unpaired t-test was carried out to compare the mean, which was found to be not significant at the 5% level (i.e.,p>0.05). It revealed that the baseline characteristics were similar in both groups.

Table 3 shows the pre and post-test outcomes of quadriceps strength among the college students between the groups. Interventions in both groups A and B were individually effective in improving the quadriceps strength in normal college students. But, while the post-test outcomes were compared between the groups, the intervention of backward walking in group B was found to be better in improving the quadriceps strength of college students.

Discussion

The present randomized controlled trial aimed to compare the effect of backward and forward walking training on pain, function, and quadriceps muscle strength. The result of the present study indicated that the backward walking program is efficient in reducing pain and improving function and quadriceps muscle strength.⁹ When comparing the motor control mechanism, BW and FW used the same rhythm circuitry but backward walking, in addition, requires specialized motor circuits.¹⁰ Backward walking, unlike forward walking, also required specialized control circuits, in addition to rhythm circuitry. The toes connect with the ground first and then the heel is lifted off the ground at the end during the backward walking stance, which leads to different muscle activation, pattern, and gait characteristics.¹¹ The moment pattern of the ankle joint seems to be similar in FW and time-reversed BW. As the main thrust during mid-stance is given by knee and hip extensors, during backward walking this could have led to increased strength. The post-test scores for backward walking were slightly higher than for forward walking. This could be because the main FW propulsion is generated by the ankle plantar flexors, and the principal BW propulsion is provided by the hip and knee extensors which could have led to increased strength in the quadriceps muscle.¹² The changes in the hip angle of BW gait seem to be time-reversed and look-alike that of FW gait, but the changes in knee and ankle angle are not. Also, the foot impact on the ground in early stance is sustained by the co-activation of several limb muscles like flexors and extensors at the hip, knee, and ankle in FW gait whereas the same event is complemented by activity in knee extensors and ankle plantar-flexors in BW gait thus it would have led to increased strength in quadriceps.¹³ The major changes in muscle activation between forward and backward walking happen in the particular thigh muscles.¹⁴ This could have led to the difference in the quadriceps strength in the backward walking group.

Conclusion

Thus this study concludes that though clinically backward walking can lead to a higher quadriceps strength but statistically both forward and backward walking can increase the quadriceps strength.

Conflicts of Interest

Nil