Long-term effects of running exercises on natural grass, artificial turf, and synthetic surfaces on ground reaction force components in individuals with overpronated feet: A randomized controlled trial.

BACKGROUND: Overpronated feet are associated with alteration of lower limb mechanics. Also, quantifying ground reaction force-related changes due to exercise on different surfaces is important for understanding the potential risk of injuries. RESEARCH QUESTION: What are the long-term effects of running exercises on natural grass, artificial turf, and synthetic surfaces on ground reaction force components in individuals with overpronated feet? METHODS: Of 82 contacted individuals with overpronated feet aged 18-30, 22 were excluded because they did not meet inclusion criteria (20), and two declined to participate. Sixty individuals were included in randomization, the control (n = 15), hard court or synthetic surface (n = 15), natural grass (n = 15), and artificial turf (n = 15) groups. There was a sample loss of 8 individuals because of personal problems (2 in each group). The intervention groups performed running exercises on natural grass, artificial turf, and synthetic surfaces over eight weeks, three sessions per week. No training or test-related injuries were reported throughout the study. A force plate was embedded midway through the 18-running concrete path to collect ground reaction force data while running on stable ground before and after interventions. RESULTS: Findings demonstrated significant group-by-time interactions for vertical loading rate (p = 0.016, ETA=0.297). Post-hoc analyses showed increased loading rate amplitude in two natural grass and artificial turf groups (but not in the control and synthetic surface groups) post-intervention. SIGNIFICANCE: Running training on natural grass and artificial turf surfaces may place individuals with overpronated feet at a higher risk of injury while running on a stable surface.

Muscle activation while running on the ground compared to artificial turf in males with pronated and supinated feet.

BACKGROUND: Running on different surfaces, including natural and artificial surfaces, requires different gait mechanics, especially in individuals with foot deformity. RESEARCH QUESTION: How muscle activity change during running on the ground and artificial turf in males with pronated and supinated feet? METHODS: In this quasi-experimental study, we assessed a cohort of young male subjects, classified as healthy (n = 10), and with pronated (n = 10) or supinated (n = 10) feet. An electromyographic system was used to record lower limb muscle activity while running on the ground and artificial turf at constant speed (3.2 m/s). RESULTS: Results demonstrated significant main effects of the "surface" factor for vastus medialis activity during the loading phase (p = 0.040, η2 =0.147). Paired comparison revealed significantly greater vastus medialis activity while running on artificial grass with respect to the ground. A significant effect of the "group" factor was found for medial gastrocnemius during loading phase (p = 0.020, η2 =0.250). Paired-wise comparison revealed significantly lower medial gastrocnemius activity in the pronated and supinated feet groups than in the healthy group. SIGNIFICANCE: The healthy group may possess better neuromuscular control, allowing them to effectively coordinate the activation of the medial gastrocnemius with other muscles involved in running. Based on these findings, running on artificial turf is useful when the runner would like to strengthen vastus medialis muscle. The runner should carefully choose the running surface according to his/her state and training session goal.

The Impact of Excessive Body Weight and Foot Pronation on Running Kinetics: A Cross-Sectional Study.

BACKGROUND: Running exercise is an effective means to enhance cardiorespiratory fitness and body composition. Besides these health benefits, running is also associated with musculoskeletal injuries that can be more prevalent in individuals with excessive body weight. Little is known regarding the specific effects of overweight and foot pronation on ground reaction force distribution during running. Therefore, this study aimed to investigate the effects of overweight/obesity and foot pronation on running kinetics. METHODS: Eighty-four young adults were allocated to four experimental groups: non-excessive body weight/non-pronated feet; non-excessive body weight/pronated feet; overweight or obesity/ non-pronated feet and overweight or obesity/pronated feet. Biomechanical testing included participants to run at ~ 3.2 m/s over an 18-m walkway with an embedded force plate at its midpoint. Three-dimensional ground reaction forces were recorded and normalized to body mass to evaluate running kinetics from 20 running trials. Test-re-test reliability for running speed data demonstrated ICC > 0.94 for each group and in total. RESULTS: The results indicated significantly lower vertical impact peak forces (p = 0.001, effect size = 0.12), shorter time to reach the vertical impact peak (p = 0.006, effect size = 0.08) and reduced vertical loading rate (p = 0.0007, effect size = 0.13) in individuals with excessive body weight (overweight or obesity/non-pronated feet group and overweight or obesity/pronated feet) compared with individuals non-excessive body weight (non-excessive body weight/non-pronated feet and non-excessive body weight/pronated feet). Moreover, the excessive body weight groups presented lower peak braking (p = 0.01, effect size = 0.06) and propulsion forces (p = 0.003, effect size = 0.09), lower medio-lateral loading rate (p = 0.0009, effect size = 0.12), and greater free moments (p = 0.01, effect size = 0.07) when compared to the non-overweight groups. Moreover, a significant body mass by foot pronation interaction was found for peak medio-lateral loading rate. Non-excessive body weight/pronated feet, excessive body weight/non-pronated feet and excessive body weight/pronation groups presented lower medio-lateral loading rates compared to non-excessive body weight/non-pronated feet (p = 0.0001, effect size = 0.13). CONCLUSIONS: Our results suggest that excessive body weight has an impact on ground reaction forces during running. We particularly noted an increase in medio-lateral and torsional forces during the stance phase. Individuals with excessive body weight appear to adapt their running patterns in an effort to attenuate early vertical impact loading.

Recreational runners who recovered from COVID-19 show different running kinetics and muscle activities compared with healthy controls.

BACKGROUND: Social isolation through quarantine represents an effective means to prevent COVID-19 infection. A negative side-effect of quarantine is low physical activity. RESEARCH QUESTION: What are the differences of running kinetics and muscle activities of recreational runners with a history of COVID-19 versus healthy controls? METHODS: Forty men and women aged 20-30 years participated in this study and were divided into two experimental groups. Group 1 (age: 24.1 ± 2.9) consisted of participants with a history of COVID-19 (COVID group) and group 2 (age: 24.2 ± 2.7) of healthy age and sex-matched controls (controls). Both groups were tested for their running kinetics using a force plate and electromyographic activities (i.e., tibialis anterior [TA], gastrocnemius medialis [Gas-M], biceps femoris [BF], semitendinosus [ST], vastus lateralis [VL], vastus medialis [VM], rectus femoris [RF], gluteus medius [Glut-M]). RESULTS: Results demonstrated higher peak vertical (p = 0.029; d=0.788) and medial (p = 0.004; d=1.119) ground reaction forces (GRFs) during push-off in COVID individuals compared with controls. Moreover, higher peak lateral GRFs were found during heel contact (p = 0.001; d=1.536) in the COVID group. COVID-19 individuals showed a shorter time-to-reach the peak vertical (p = 0.001; d=3.779) and posterior GRFs (p = 0.005; d=1.099) during heel contact. Moreover, the COVID group showed higher Gas-M (p = 0.007; d=1.109) and lower VM activity (p = 0.026; d=0.811) at heel contact. SIGNIFICANCE: Different running kinetics and muscle activities were found in COVID-19 individuals versus healthy controls. Therefore, practitioners and therapists are advised to implement balance and/or strength training to improve lower limbs alignment and mediolateral control during dynamic movements in runners who recovered from COVID-19.