Protocol for evaluating the effects of a therapeutic foot exercise program on injury incidence, foot functionality and biomechanics in long-distance runners: a randomized controlled trial

Running intralimb coordination patterns after a foot core exercise program in recreational runners

This study investigated the effects of a foot core intervention on the coordination of foot joints in recreational runners. This was a secondary analysis from a randomized controlled trial conducted with 87 recreational runners allocated to the control group (CG), which followed a placebo lower limb stretching protocol, or the intervention group (IG), which underwent an 8-week (3 times/week) foot core training. The participants ran on a force-instrumented treadmill at a self-selected speed (9.5-10.5 km/h) while the foot segment motion was captured. The vector coding technique was used to assess inter-joint coordination for four selected coupled segment and joint angles. The coordination patterns of the calcaneus and midfoot (CalMid) and midfoot and metatarsus (MidMet) joint pairs were affected. In the frontal plane, IG showed an in-phase with proximal dominancy coordination at heel strike, with a decrease in its frequency after the training (P=0.018), suggesting a longer foot supination. Additionally, IG showed an anti-phase with distal dominancy pattern at early stance compared to CG due to a smaller but earlier inversion of the CalMid-MidMet pair (P=0.020). The intervention also had an effect on the transverse plane of the CalMid-MidMet pair, with IG showing a significantly greater frequency of anti-phase coordination with proximal dominancy during propulsion than CG (P=0.013), probably due to a reduction in the CalMid abduction. Overall, the results suggested that the foot core intervention reduces the occurrence of running-related injuries by increasing the resistance to calcaneus pronation and building a more rigid and efficient lever during push-off.

Rehabilitation of anterior knee pain in the pregnant athlete: Considerations and modifications by trimester

BACKGROUND

Anterior knee pain is a common symptom many females experience during pregnancy. There are several musculoskeletal changes that occur in anatomy and physiology throughout the course of pregnancy that impact the lower extremity kinetic chain. Pregnant athletes, recreational through competitive, who attempt to maintain a high activity level through each trimester may be at increased risk for anterior knee pain due to a greater demand for lumbopelvic and hip stabilization.

CLINICAL QUESTION

What are the evidence-driven rehabilitation guidelines and specific modifications needed to treat anterior knee pain in the female athlete during each trimester of pregnancy?

KEY RESULTS

We aim to provide an overview of rehabilitation treatment guidelines for pregnant females with anterior knee pain, presenting specific physiological changes and rationale for modifications, discussed by trimester. We recommend our program be conducted under the supervision of a physical therapist working closely with the athlete's obstetrics and sports medicine team.

CLINICAL APPLICATION

The number of women who are active during pregnancy is increasing. We provide an overview of the guidelines and considerations for treating women with anterior knee pain during a healthy and uneventful pregnancy.

Effect of intrinsic foot muscles training on foot function and dynamic postural balance: A systematic review and meta-analysis

This systematic review aimed to analyse the effects of intrinsic foot muscle (IFM) training on foot function and dynamic postural balance. Keywords related to IFM training were used to search four databases (PubMed, CINAHL, SPORTDiscus and Web of Science databases.) for relevant studies published between January 2011 and February 2021. The methodological quality of the intervention studies was assessed independently by two reviewers by using the modified Downs and Black quality index. Publication bias was also assessed on the basis of funnel plots. This study was registered in PROSPERO (CRD42021232984). Sixteen studies met the inclusion criteria (10 with high quality and 6 with moderate quality). Numerous biomechanical variables were evaluated after IFM training intervention. These variables included IFM characteristics, medial longitudinal arch morphology and dynamic postural balance. This systematic review demonstrated that IFM training can exert positive biomechanical effects on the medial longitudinal arch, improve dynamic postural balance and act as an important training method for sports enthusiasts. Future studies should optimise standardised IFM training methods in accordance with the demands of different sports.

Effects of Foot-Core Training on Foot-Ankle Kinematics and Running Kinetics in Runners: Secondary Outcomes From a Randomized Controlled Trial

This study investigated the effectiveness of an 8-week foot-core exercise training program on foot-ankle kinematics during running and also on running kinetics (impact loads), with particular interest in biomechanical outcomes considered risk factors for running-related injuries in recreational runners. A single-blind, randomized, controlled trial was conducted with 87 recreational runners randomly allocated to either the control (CG) or intervention (IG) group and assessed at baseline and after 8 weeks. The IG underwent foot-core training 3 times/week, while the CG followed a placebo lower-limb stretching protocol. The participants ran on a force-instrumented treadmill at a self-selected speed while foot-segment motion was captured simultaneously with kinetic measurements. After the intervention, there were statistically significant changed in foot biomechanics, such as: IG participants strike the ground with a more inverted calcaneus and a less dorsiflexed midfoot than those in the CG; at midstance, ran with a less plantarflexed and more adducted forefoot and a more abducted hallux; and at push-off, ran with a less dorsiflexed midfoot and a less adducted and more dorsiflexed hallux. The IG runners also had significantly decreased medial longitudinal arch excursion (p = 0.024) and increased rearfoot inversion (p = 0.037). The 8-week foot-core exercise program had no effect on impact (p = 0.129) and breaking forces (p = 0.934) or on vertical loading rate (p = 0.537), but it was positively effective in changing foot-ankle kinematic patterns.”

Injury Prevention, Safe Training Techniques, Rehabilitation, and Return to Sport in Trail Runners

This current concept, narrative review provides the latest integrated evidence of the musculoskeletal injuries involved with trail running and therapeutic strategies to prevent injury and promote safe participation. Running activities that comprise any form of off-road running (trail running, orienteering, short-long distance, different terrain, and climate) are relevant to this review. Literature searches were conducted to 1) identify types and mechanisms of acute and chronic/overuse musculoskeletal injuries in trail runners, 2) injury prevention techniques most relevant to running trails, 3) safe methods of participation and rehabilitation timelines in the sport. The majority of acute and chronic trail running-related musculoskeletal injuries in trail running occur in the lower leg, primarily in the knee and ankle. More than 70% are due to overuse, and ankle sprains are the most common acute injury. Key mechanisms underlying injury and injury progression include inadequate neuromotor control-balance-coordination, running through fatigue, and abnormal kinematics on variable terrain. Complete kinetic chain prehabilitation programs consisting of dynamic flexibility, neuromotor strength and balance, and plyometrics exercise can foster stable, controlled movement on trails. Patient education about early musculoskeletal pain symptoms and training adjustment can help prevent injury from progressing to serious overuse injuries. Real-time adjustments to cadence, step length, and knee flexion on the trail may also mitigate impact-related risk for injury. After injury occurs, rehabilitation will involve similar exercise components, but it will also incorporate rest and active rest based on the type of injury. Multicomponent prehabilitation can help prevent musculoskeletal injuries in trail runners through movement control and fatigue resistance.

Predictive Effect of Well-Known Risk Factors and Foot-Core Training in Lower Limb Running-Related Injuries in Recreational Runners: A Secondary Analysis of a Randomized Controlled Trial

BACKGROUND

Running carries the risk of several types of running-related injuries (RRIs), especially in the lower limbs. The variety of risk factors and the lack of strong evidence for several of these injury risks hinder the ability to draw assertive conclusions about them, hampering the implementation of effective preventive strategies. Because the etiology of RRIs seems to be multifactorial, the presence of RRI risk factors might influence the outcome of therapeutic strategies in different ways. Thus, further investigations on how risk and protective factors influence the incidence and prevention of RRIs should be conducted.

PURPOSE

To investigate the predictive effect of well-known risk factors and 1 protective factor-foot-core training-on the incidence of lower limb RRIs in recreational runners.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

Middle- and long-distance recreational runners (N = 118) were assessed at baseline and randomly allocated to either an intervention group (n = 57) or a control group (n = 61). The intervention group underwent an 8-week (3 times/wk) foot-core training program. Participants were followed for a year after baseline assessment for the occurrence of RRIs. Logistic regression with backward elimination of variables was used to develop a model for prediction of RRI in recreational runners. Candidate predictor variables included age, sex, body mass index, years of running practice, number of races, training volume, training frequency, previous RRI, and the foot-core exercise training.

RESULTS

The final logistic regression model included 3 variables. As previously shown, the foot-core exercise program is a protective factor for RRIs (odds ratio, 0.40; 95% CI, 0.15-0.98). In addition, older age (odds ratio, 1.07; 95% CI, 1.00-1.14) and higher training volume (odds ratio, 1.02; 95% CI, 1.00-1.03) were risk factors for RRIs.

CONCLUSION

The foot-core training was identified as a protective effect against lower limb RRI, which can be negatively influenced by older age and higher weekly training volume. The predictive model showed that RRIs should be considered a multivariate entity owing to the interaction among several factors.

REGISTRATION

NCT02306148 (ClinicalTrials.gov identifier).

Subgroups of Foot-Ankle Movement Patterns Can Influence the Responsiveness to a Foot-Core Exercise Program: A Hierarchical Cluster Analysis

The purpose of this study is to identify homogenous subgroups of foot-ankle (FA) kinematic patterns among recreational runners and further investigate whether differences in baseline movement patterns can influence the mechanical responses to a foot-core exercise intervention program. This is a secondary analysis of data from 85 participants of a randomized controlled trial (clinicaltrials.gov - NCT02306148) investigating the effects of an exercise-based therapeutic approach focused on FA complex. A validated skin marker-based multi-segment foot model was used to acquire kinematic data during the stance phase of treadmill running. Kinematic features were extracted from the time-series data using a principal component analysis, and the reduced data served as input for a hierarchical cluster analysis to identify subgroups of FA movement patterns. FA angle time series were compared between identified clusters and the mechanical effects of the foot-core exercise intervention was assessed for each subgroup. Two clusters of FA running patterns were identified, with cluster 1 (n = 36) presenting a pattern of forefoot abduction, while cluster 2 (n = 49) displayed deviations in the proximal segments, with a rearfoot adduction and midfoot abduction throughout the stance phase of running. Data from 29 runners who completed the intervention protocol were analyzed after 8-weeks of foot-core exercises, resulting in changes mainly in cluster 1 (n = 16) in the transverse plane, in which we observed a reduction in the forefoot abduction, an increase in the rearfoot adduction and an approximation of their pattern to the runners in cluster 2 (n = 13). The findings of this study may help guide individual-centered treatment strategies, taking into account their initial mechanical patterns.

Foot Core Training to Prevent Running-Related Injuries: A Survival Analysis of a Single-Blind, Randomized Controlled Trial

BACKGROUND

Running-related injuries (RRIs) are a pervasive menace that can interrupt or end the participation of recreational runners in this healthy physical activity. To date, no satisfactory treatment has been developed to prevent RRIs.

PURPOSE

To investigate the efficacy of a novel foot core strengthening protocol based on a ground-up approach to reduce the incidence of RRIs in recreational long-distance runners over the course of a 1-year follow-up.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

METHODS

The participants, 118 runners, were assessed at baseline and randomly allocated to either an intervention group (n = 57) or a control group (n = 61). The intervention group received an 8-week training course focused on the foot-ankle muscles, followed by remotely supervised training thereafter. Assessments consisted of 3 separate biomechanical evaluations of foot strength and foot posture and a weekly report on each participant's running distance, pace, and injury incidence over 12 months.

RESULTS

The control group participants were 2.42 times (95% CI, 1.98-3.62) more likely to experience an RRI within the 12-month study period than participants in the intervention group (P = .035). Time to injury was significantly correlated with Foot Posture Index (P = .031; r = 0.41) and foot strength gain (P = .044; r = 0.45) scores. This foot exercise program showed evidence of effective RRI risk reduction in recreational runners at 4 to 8 months of training.

CONCLUSION

Recreational runners randomized to the new foot core strengthening protocol had a 2.42-fold lower rate of RRIs compared with the control group. Further studies are recommended to better understand the underlying biomechanical mechanisms of injury, types of injuries, and subgroups of runners who might benefit maximally.

REGISTRATION

NCT02306148 (ClinicalTrials.gov identifier).

Strength Training Habits in Amateur Endurance Runners in Spain: Influence of Athletic Level

This study determined the strength training (ST) habits of amateur endurance runners in Spain regarding athletic level. A sixteen-item online questionnaire comprised of (i) demographic information, (ii) performance, and (iii) training contents was completed by 1179 athletes. Five group levels were determined according to the personal best times of the athletes in a 10-km trial (LG1: level group 1, 50–55 min; LG2: level group 2, 45–50 min; LG3: level group 3, 40–45 min; LG4: level group 4, 35–40 min; LG5: level group 5, 30–35 min). Most athletes (n = 735, 62.3%) perceived ST as being a key component in their training program. Resistance training (RT) was reported as a ST type used by 63.4% of the athletes, 66.9% reported using bodyweight exercises, 46.8% reported using plyometric training, 65.6% reported using uphill runs, and 17.8% reported using resisted runs. The prevalence of runners who excluded ST from their training programs decreased as the athletic performance level increased (18.2% in lower-level athletes vs. 3.0% in higher-level), while the inclusion of RT, bodyweight exercises, plyometric training, and uphill and resisted runs was more frequent within higher-level groups. Most athletes included ST using low-to-moderate loads and high a number of repetitions/sets comprised of RT, plyometric training, resisted runs, and core, respiratory, and foot muscles training.

The association between high-arched feet, plantar pressure distribution and body posture in young women

The aim of this study was to examine the effect of excessive feet arching (symmetrical and asymmetrical) on plantar pressure distribution and on the alignment of pelvis, spine and shoulder girdle. Eighty-one women (20-40 years old, 61 +/- 12 kg, 165 +/- 5 cm) were divided into 3 groups based on the foot arch index (Group 1 - with normally arched feet, Group 2 with one foot properly arched and the other high-arched, Group 3 with both feet high-arched). Plantar pressure distribution between the right and left foot for the forefoot, midfoot and rearfoot, respectively and body posture were assessed. A slight increase in longitudinal arch of the foot caused changes in the distribution of feet loads both between limbs and between the forefoot and rearfoot and also influenced the whole body. Asymmetrical high-arching of the feet resulted in asymmetry of lower limb load and in the height of the shoulder girdle. We have suggested that any alteration of the foot arch may be harmful to body tissues and should not be considered as correct. Due to the fact that slight increases in longitudinal arch of the foot are very common, they should be considered as a foot defect, and appropriate corrective exercises should be used to prevent forefoot overload and alterations in body posture.

The Influence of Plantar Short Foot Muscle Exercises on the Lower Extremity Muscle Strength and Power in Proximal Segments of the Kinematic Chain in Long-Distance Runners

The aim of this study was to evaluate the influence of plantar short foot muscles exercises on the performance of lower extremities in long-distance runners. 47 long-distance runners aged 21-45 years took part in this study. The participants were divided into two groups based on baseline measurement of Foot Posture Index: Group 1 (n=27) with neutral foot and Group 2 (n=20) with slight and increased pronation. The participants performed the exercises daily for 6 weeks. The knee flexors and extensors torque, work, and power on Isokinetic Dynamometer and Running-Based Anaerobic Sprint Test (RAST) were checked at baseline and after 6 weeks of exercises. Higher values of peak torque of knee flexors were observed. This change was statistically significant at high load with angular velocity 90°/s (73.55 Nm at baseline and 89.05 Nm after 6 weeks) and 160°/s (69.40 Nm at baseline and 79.00 Nm after 6 weeks) in Group 2. In both groups higher values of maximum power were noted. Participants in Group 2 achieved lower values in each 35-metre run time and higher values of power. In Group 2 there was significant improvement of total time (35.26 s at baseline and 34.79 s after 6 weeks) compared to Group 1 (37.33 s at baseline and 37.56 s after 6 weeks). Exercises strengthening short foot muscles may improve energy transfer through body segments and increase strength and values of generated power. They should be included as a part of daily training programme of runners. This study was registered in the Australian New Zealand Clinical Trials Registry (ANZCTR). Registration number: ACTRN12615001200572.