Barefoot running on grass as a potential treatment for plantar fasciitis: a prospective case series

Key Points

1. This study presents a case series of recreational runners with plantar heel pain who undertook a barefoot running intervention on grass for six weeks.
2. Small reductions in pain were reported following the intervention.
3. Due to study limitations, further research is required to determine the beneficial effect that may be expected in clinical practice.

BACKGROUND & OBJECTIVE

Plantar heel pain - the contemporary term that encompasses plantar fasciitis – is a common cause of foot pain in both athletic (active) and non-athletic (sedentary) individuals. Most plantar heel pain research has been conducted in non-athletic populations and there is limited research that reports treatment outcomes in athletic populations, including athletic-specific interventions (1).

This study presented a case series of runners with plantar heel pain who undertook a barefoot running intervention on grass.

There is limited research on plantar heel pain that reports treatment outcomes in athletic populations.

For at least a subset of recreational runners, barefoot running (on grass) might be a feasible/tolerated treatment option.

METHODS

• 28 recreational runners (minimum 5km/week) with existing symptoms of plantar heel pain participated in the study.

• All participants were prescribed the same intervention which involved running barefoot on grass for 15 minutes (at rate of perceived exertion of 11 – “light / fairly easy”) every second day for 6 weeks (21 sessions).

• An online survey was completed daily to record activity (rest day / ran 15 min on grass barefoot / other) and morning pain (using numerical rating scale where zero is no pain at all, ten is the worst pain imaginable).

• Participants were requested not to seek other treatment during the study duration and to continue usual activities of daily living.

• Participants who failed to fill out the online survey on two consecutive days were excluded from the study.

• Participant follow-up was conducted at 6 and 12 weeks.

RESULTS

• Eight participants (29%) were excluded for incomplete data capture / did not complete the daily online survey.

• 20 participants (71%) were included in the analysis (10 males, 10 females; mean age 48 years +/- 8, range 34 - 65 years). Participants reported symptoms for between 3 and 48 months (median 7.5 months).

• Previous treatment reported by participants included physiotherapy (9/45%) and shockwave therapy (2/10%), with eight (40%) participants reporting they had not received prior treatment.

• Compliance to the running intervention (15 min barefoot running on grass every second day) was 76.2% (16.1 sessions from a maximum 21).

• Figure 1 illustrates pain scores during the 6-week intervention and at 12-week follow-up. Morning pain was lower at 6- and 12-week follow-up.

• At 12-week follow-up, 18/20 (90%) said they would recommend the intervention to someone else with their condition, 12 (60%) were running at least 5km twice weekly in shoes and on the road and one participant continued to run barefoot on grass.

LIMITATIONS

• Case series design (absence of control group and random allocation to intervention)

• Minimal description of participant characteristics was provided. Participants satisfied a minimum criterion of 5km/week, but no quantification of actual running mileage was provided, or other aspects such as typical footwear, foot strike pattern, time spent barefoot, body mass index.

• Results were reported per protocol. Exclusion of 29% participants who did not complete the daily online survey introduces potential bias and must be considered when interpreting the results. No description of the characteristics of the excluded participants was provided, hence the residual group that was analysed may not represent the original group recruited. It is unknown if experience of unacceptable side effects was related to missing data (those who failed to complete daily survey).

CLINICAL IMPLICATIONS

Due to the absence of a control group, it is unclear if the running intervention provides beneficial outcomes beyond natural course of the condition. As eight participants (29%) were excluded from the analysis for incomplete data (analysis per protocol), this study provides an estimate of the efficacy of the intervention but may not represent the real-life situation and is therefore likely to report an exaggerated treatment effect. Results may not accurately reflect the beneficial effect that may be expected in clinical practice among those who were prescribed this treatment.

Despite these limitations, case series are an essential part of building knowledge and posing new hypotheses. This is particularly relevant in this field of plantar heel pain research where there are limited studies that investigate athletic specific interventions and/or active populations.

It might be considered counterintuitive to prescribe running (a vigorous weight bearing/impact activity) without shoes for an individual with symptomatic plantar heel pain. Indeed, footwear advice for individuals with plantar heel pain typically involves recommendations of softness, shock absorption, rearfoot to forefoot drop and support (2). This study suggests that – for at least a subset of recreational runners – barefoot running (on grass) might be feasible/tolerated.

The authors reported statistically significant reductions in morning pain at 6- and 12-week follow-up. Previous research suggests that the minimal clinically important change in pain (measured by numerical rating scale) is 2-points or 33% (3). Results of this case series suggest that with a 6-week intervention of barefoot running on grass small reductions in morning pain were observed at 6 weeks (1.4 points, 38.8%) and were likely more meaningful at 12-weeks (2.4 points, 58.3%).

+STUDY REFERENCE

MacGabhann S, Kearney D, Perrem N, Francis P (2022) Barefoot Running on Grass as a Potential Treatment for Plantar Fasciitis: A Prospective Case Series. Int. J. Environ. Res. Public Health, 19(23), 15466.

SUPPORTING REFERENCE

1. Harvey, H. D., Game, C., Walsh, T. P., Wearing, S. C., & Platt, S. R. (2022). Are models of plantar heel pain suitable for competitive runners? A narrative review. Journal of orthopaedics, 33, 9-14.
2. Salaffi, F., Stancati, A., Silvestri, C. A., Ciapetti, A., & Grassi, W. (2004). Minimal clinically important changes in chronic musculoskeletal pain intensity measured on a numerical rating scale. Eur J Pain, 8(4), 283-291.
3. Morrissey, D., Cotchett, M., Said J'Bari, A., Prior, T., Griffiths, I. B., Rathleff, M. S., Gulle, H., Vicenzino, B., & Barton, C. J. (2021). Management of plantar heel pain: a best practice guide informed by a systematic review, expert clinical reasoning and patient values. Br J Sports Med, 55(19), 1106-1118.