Tokuda Y1, Saito E1, Kihara Y1, Hoshino Y1
1Teikyo Heisei University, Physical Therapy, Tokyo, Japan
Background: According to a Japanese report, about 65％ of runners have experienced an injury. Good running technique reduces injury. Generally, initial contact during running is through a rear foot strike (RFS), as in walking. Sprinters and some marathon runners have been using a fore foot strike (FFS) to increase running speed, but there is little scientific evidence for the advantages and disadvantages of FFS technique.
Purpose: The objective of this study was to clarify the characteristics of FFS and RFS using motion analysis.
Methods: We enrolled healthy 8 males (age: 20 to 22 years, height: 172.6±3.9 cm, weight: 63.5±5.5 kg) and 10 females (age: 20 to 22 years, height: 157.6±4.2 cm, weight: 53.7±6.2 kg). A three dimensional motion analysis system (Vicon Nexus 2) and a force plate (Kistler) were used. Sampling frequency was 100 Hz for the Vicon Nexus 2 and 1,000 Hz for the Kistler force plate. We applied 16 reflective body markers (Vicon Plug-in Gait lower body model) to each subject. The subjects ran barefoot on a nine meters running path in the laboratory, using RFS and FFS technique in random order. Instructions were given to maintain moderate running speed without an intentional change. Speed, stride length, reaction force, and ankle angular velocity and ankle moment per body weight were measured using both methods. Statistical analysis was performed with Wilcoxon signed-rank test at a 5% significance level.
Results: The following results were obtained (expressed as median ± quartile deviation):
1) Speed with FFS technique (3.2±0.3 m/s) was significantly greater than that with RFS technique (3.0±0.3 m/s). Stance phase time with FFS technique (0.22±0.02 s) was significantly shorter than that with RFS technique (0.24±0.02 s). Stride length was not significantly difference between FFS technique (2.2±0.2 m) and RFS technique (2.1±0.1 m).
2) The maximum vertical reaction force with FFS technique (1,606.1±189.1 N) was significantly greater than that with RFS technique (1,376.0±50.0 N). The maximum progressive reaction force with FFS technique (260.9±43.8 N) was significantly greater than that with RFS technique (202.4±24.0 N). At the moment of maximum vertical reaction force, most of the progressive reaction force with FFS technique was in a forward direction while that with RFS technique was still in a backward direction.
3) From initial contact to mid-stance, the increase in ankle dorsi flexion angle with FFS technique (31.9±4.5°) was significantly greater than that with RFS technique (17.4±5.1°). From mid-stance to
terminal stance, ankle angular velocity for plantar flexion with FFS technique (473.3±53.3 deg/s) was significantly greater than that with RFS technique (428.3±66.3 deg/s). The maximum ankle moment per body weight with FFS technique(3.3±0.6 N m/kg) was significantly greater than that with RFS technique (2.3±0.4 N m/kg).
Conclusion(s): FFS technique increased running speed, maximum vertical and progressive reaction force, ankle angular velocity and maximum ankle moment. These results suggest that FFS technique may be good for running faster, but with higher loads.
Implications: This study suggested that FFS technique may increase running loads. These results may be useful for prevention of running injuries.
Keywords: motion analysis, running, fore foot strike
Funding acknowledgements: This work was not supported by any foundation.
Purpose: The objective of this study was to clarify the characteristics of FFS and RFS using motion analysis.
Methods: We enrolled healthy 8 males (age: 20 to 22 years, height: 172.6±3.9 cm, weight: 63.5±5.5 kg) and 10 females (age: 20 to 22 years, height: 157.6±4.2 cm, weight: 53.7±6.2 kg). A three dimensional motion analysis system (Vicon Nexus 2) and a force plate (Kistler) were used. Sampling frequency was 100 Hz for the Vicon Nexus 2 and 1,000 Hz for the Kistler force plate. We applied 16 reflective body markers (Vicon Plug-in Gait lower body model) to each subject. The subjects ran barefoot on a nine meters running path in the laboratory, using RFS and FFS technique in random order. Instructions were given to maintain moderate running speed without an intentional change. Speed, stride length, reaction force, and ankle angular velocity and ankle moment per body weight were measured using both methods. Statistical analysis was performed with Wilcoxon signed-rank test at a 5% significance level.
Results: The following results were obtained (expressed as median ± quartile deviation):
1) Speed with FFS technique (3.2±0.3 m/s) was significantly greater than that with RFS technique (3.0±0.3 m/s). Stance phase time with FFS technique (0.22±0.02 s) was significantly shorter than that with RFS technique (0.24±0.02 s). Stride length was not significantly difference between FFS technique (2.2±0.2 m) and RFS technique (2.1±0.1 m).
2) The maximum vertical reaction force with FFS technique (1,606.1±189.1 N) was significantly greater than that with RFS technique (1,376.0±50.0 N). The maximum progressive reaction force with FFS technique (260.9±43.8 N) was significantly greater than that with RFS technique (202.4±24.0 N). At the moment of maximum vertical reaction force, most of the progressive reaction force with FFS technique was in a forward direction while that with RFS technique was still in a backward direction.
3) From initial contact to mid-stance, the increase in ankle dorsi flexion angle with FFS technique (31.9±4.5°) was significantly greater than that with RFS technique (17.4±5.1°). From mid-stance to
terminal stance, ankle angular velocity for plantar flexion with FFS technique (473.3±53.3 deg/s) was significantly greater than that with RFS technique (428.3±66.3 deg/s). The maximum ankle moment per body weight with FFS technique(3.3±0.6 N m/kg) was significantly greater than that with RFS technique (2.3±0.4 N m/kg).
Conclusion(s): FFS technique increased running speed, maximum vertical and progressive reaction force, ankle angular velocity and maximum ankle moment. These results suggest that FFS technique may be good for running faster, but with higher loads.
Implications: This study suggested that FFS technique may increase running loads. These results may be useful for prevention of running injuries.
Keywords: motion analysis, running, fore foot strike
Funding acknowledgements: This work was not supported by any foundation.
Topic: Human movement analysis; Sport & sports injuries; Occupational health & ergonomics
Ethics approval required: Yes
Institution: Teikyo Heisei University
Ethics committee: The Ethics Committee of Teikyo Heisei University
Ethics number: No. 30-016
All authors, affiliations and abstracts have been published as submitted.
