VIBRAM Five Fingers, mai fermarsi ai titoli

continue analisi e discussioni

Le scarpe minimaliste continuano a far discutere: la scienza e il marketing non procedono solo con teorie e slogan, ma anche con suggestive dimostrazioni per avvalorarli. Così a parità di oggetto di indagine spesso si raggiungono risultati apparentemente discordi, secondo l'aspetto che si intende evidenziare.

Ecco due recenti studi su VIBRAM Five Fingers di cui vi offro subito l'estrema sintesi: funzionano (vd. @RW_04/01) con cautela (vd. @RW_27/02), come dice anche Jill COOK (vd. post 04/03). Ognuno poi si legga le argomentazioni nelle 6'500 e 3'500 battute in inglese potabile dei due articoli. A voi alcune note e gli abstract originali ...

@RW_04/01 Running Economy Improves After 4 Weeks in Vibram FiveFingers

Vero! Cavie 15 runner esperti con un personale medio di 4'00" sui 1'500m (= 2'40"/km o 22,5km/h), quindi atleti abituati alle sollecitazioni delle scarpe chiodate in pista. Nell'articolo si trova il protocollo di utilizzo e di misura: da leggere con attenzione! Due punti deboli: la velocità limitata di esecuzione del test (11 e 13km/h), il confronto con ASICS Nimbus tanto lontana da VIBRAM Five Fingers (perché non utilizzare una racing flat?). Nota importante: VIBRAM did not fund the study.

Abstract. The purpose of this study was to evaluate the effects of a 4-week familiarization to simulated barefoot running (SBR) on running economy (RE) when compared with shod running. Fifteen trained male runners (age: 24 ± 4 years; stature: 177.2 ± 6.21 cm; mass: 67.99 ± 7.36 kg and VO(2max) 70.2 ± 5.2 mL/kg/min) were recruited. Subjects completed two RE tests, 24 h apart, in a random order, in both the SBR and shod condition (pretest) at 11 km/h and 13 km/h. Oxygen uptake, heart rate, stride frequency, and foot strike patterns were measured in both conditions. Subjects then completed a 4-week familiarization period of SBR, before repeating the two RE tests (post-test). At pretest, there was no significant difference in RE between SBR and shod running (P = 0.463), but following the 4-week familiarization period, RE significantly improved by 6.9% in the SBR condition compared with shod running (46.4 ± 0.9 vs 43.2 ± 1.2 mL/kg/min; P = 0.011). A significant improvement in RE was observed in the SBR condition (8.09%) between the pretest and post-test (47.0 ± 1.2 vs 43.2 ± 1.2 mL/kg/min; P = 0.002). RE improved in the SBR condition as a result of familiarization, and became significantly lower in SBR compared with shod running.

@RW_27/02 Study: Vibram FiveFingers Lead to Greater Risk of Foot Bone Injury

Qui si parla di 19 giovani amatori che provano a seguire i consigli per l'utilizzo delle Five Fingers indicati dalla stessa VIBRAM due anni or sono confrontati con un gruppo di controllo composto da 17 runner (età media 26 anni, 25-45km/settimana nell'insieme): 10 hanno sviluppato sofferenza ossea ai piedi misurata con RMN dopo 10 settimane.

Purpose. Minimalist running shoes are becoming a more popular choice for runners in the past few years. However, there is little conclusive evidence about the advantages or disadvantages of running in these shoes. While performance benefits may exist, injury may also occur from the added stress of running without the benefit of cushioning under the foot. Bone marrow edema can be a manifestation of added stress on the foot. This study measured bone marrow edema in runners' feet before and after a 10 week period of transitioning from traditional to minimalist running shoes.
Methods. Thirty-six experienced, recreational runners underwent MRIs before and after a 10 week period. Seventeen subjects were in the control group (ran in their traditional shoes only for 10 weeks), while the other 19 were in the experimental group (gradually transitioned to VibramFiveFinger running shoes over 10 weeks). The severity of the bone marrow edema was scored on a range of 0-4 (0 = no bone marrow edema, 3 = edema in more than 50% of the length of the bone). A score of 4 represented a stress fracture.
Results. Pre-training MRI scores were not statistically different between the groups. The post-training MRI scores showed that more subjects in the Vibram group (10 of 19) showed increases in bone marrow edema in at least one bone after the 10 weeks of running than in the control group (p = .009).
Conclusions. Runners interested in transitioning to minimalist running shoes, such as Vibram FiveFingers should transition very slowly and gradually in order to avoid potential stress injury in the foot.

Da seguire quindi i consigli più cautelativi indicati alla fine dell'articolo @RW_27/02!

PS questo è il linguaggio delle ricerche di cui si abbevera Jill COOK (vd. post 04/03) e donde derivano le sue sentenze "NO EVIDENCE"