Gait Speed and Evolution of Verbal Fluencies in Frail or Prefrail Older People with Type 2 Diabetes. A Pilot Study.

OBJECTIVES: Type 2 diabetes (T2D) is a risk factor of frailty and cognitive impairment. Impaired gait in older people is associated with incident vascular dementia. We aimed to assess whether in frail or prefrail older subjects with T2D, lower gait speed can be associated with faster cognitive decline. DESIGN: Case-control study nested in a large randomized control trial (RCT, MID-frail); post hoc analysis. SETTING AND PARTICIPANTS: Older frail and prefrail subjects (>70y) with T2D and with no history of cognitive problems were enrolled in a single recruiting center. Participants were divided into two groups depending on their walking speed - above (fast walkers) or below (slow walkers) using a cut off of 1 m/sec. MEASURE: Cognitive function was assessed at baseline and during follow-up with the MMSE, category and letter fluencies at 15 sec (initiation) and 15-60 sec (late). RESULTS: 48 subjects were included, 22 were fast walkers, 26 were slow walkers. The mean follow-up was 60.9 (SD 17.5) weeks. The baseline 0-15 sec letter fluency was higher in fast walkers (p=0.008). There was no difference at baseline with MMSE scores and category fluency. The MID-Frail intervention did not change the evolution of any cognitive changes. Comparisons were adjusted for age, sex and baseline performance, and showed a steeper decline of category fluency score in slow walkers (fast walkers +0.04 (-1.49 to1.56) compared with -0.89 (-2.15 to 0.38), p=0.049) with a moderate effect size. CONCLUSION: In frail or prefrail older adults with diabetes, we observed a decline in category fluency in those with low gait speed.

Design of a Physical Activity Program to Prevent Functional Decline in Onco-Geriatric Patients (CAPADOGE): A Randomized Multicenter Trial.

BACKGROUND: Cancer in older patient favours the development of frailty: feeling of exhaustion, loss of weight, decreased muscle strength, slow gait speed, and low physical activity. OBJECTIVES: To evaluate the efficacy of adapted physical activity phone advices in limiting the cancer-induced loss of autonomy and frailty phenotype development. DESIGN: Multicenter randomized controlled trial. SETTING: Patients (>70y) undergoing curative treatment for cancer (n=400) will be recruited from 12 centres. INTERVENTION: The intervention consists in phoned personalized physical activity advices related to strength, aerobic, balance, proprioception, and flexibility. The contacts are performed twice a month during six months and then monthly until 1 year. The intervention complements the PNNS booklet advices (National Nutritional Health Program). The trial compares «individualized phone advices + PNNS¼ to «usual care + PNNS¼. MEASUREMENTS: Functional, cognitive, clinical and self-reported data are assessed before treatment and at 3, 6, 12, 18, and 24 month follow-up. The primary outcome is the proportion of subjects with a one-year decreased SPPB (Short Physical Performance Battery) score of one point or more, as compared to baseline. The secondary outcomes include quality of life items, rate of hospitalizations, institutionalizations, mortality, Fried phenotype at 1 and 2 years, and the SPPB score at 2 years. DISCUSSION: This large trial will provide clinical data of the effects of an exercise advices intervention in older patients during cancer therapy on function and cognition evolution, and quality of life. The possibilities of minimizing the development of frailty phenotype due to these advices will be explored.

[Effects of unilateral fatigue of triceps surae on undisturbed stance]. / Effets d'une fatigue unilatérale du triceps surae sur la posture non-perturbée.

OBJECTIVE: Fatigue of lower limb presents various impacts on postural control. The purpose of this study was to explore the effects of a unilateral lower-limb muscle fatigue on undisturbed stance. METHODS: Nine healthy men performed until exhaustion a fatiguing exercise of the limb extensor muscles of one leg (exercised leg). Just before and after the fatiguing exercise, postural sway measures (centre of pressure) were recorded simultaneously from a double force platform and an in-shoe pressure system in quiet standing conditions. Maximal plantar pressure was computed from each sensor of the in-shoe system, before being averaged for the medial and lateral heel, the external mid-foot, the external and internal foreparts. RESULTS: In undisturbed stance, the fatiguing exercise induced postural destabilisation for the non-exercised leg (P < 0.001). Changes in antero-posterior mean position of the exercised leg were also observed reflecting a mean loading in a more rear foot stance (P < 0.01). The in-shoe system parameters revealed for the exercised foot, an increase of the maximal pressure value for the heel region (P < 0.05) and a decrease for the mid-foot and forepart (P < 0.05). For the non-exercised foot, the maximal pressure decreased only in forepart (P < 0.05). CONCLUSIONS: Unilateral triceps surae fatigue revealed an immediate destabilisation of undisturbed stance and the observed postural strategy appears similar to these developed by patients who presented pain pathology and/or sensory deficits in lower limb.

Unilateral lower limb muscle fatigue induces bilateral effects on undisturbed stance and muscle EMG activities.

The study investigated the effects of an unilateral ankle muscle fatigue onto independent postural control parameters including the trajectories of the estimated resultant CoP (CoPres) and his components: the centre of gravity (CG) and CoP-CG trajectories. Nine healthy men realized series of 10 toe-lift immediately followed by 10 knee flexions until exhaustion with one (Ex) leg. Maximal isometric voluntary contractions, postural sway measures of each leg, and muscular activities of the ankle muscles were recorded before and immediately after the fatiguing exercise. As expected, the latter induced a decrease in maximal voluntary peak force associated with a greater variability of the relative contribution of each leg on the CoPres, enhanced all postural parameters of the non-exercised leg. A significant decreased of the tibialis anterior EMG activity for the Ex leg and an increased one for the NoEx leg. Finally, following unilateral fatigue, the body sway destabilisation seemed to occur only along the medio-lateral (ML) axis. The enhanced and greater variability of the variance along ML axis might be explained by the recourse at the loading-unloading strategy choice and suggests a central attempt to compensate for pain sensation.

Wearing shoes increasing dorsiflexion improves short-term but not long-term balance control in young healthy adults.

Wearing sport shoes inducing ankle dorsiflexion has been shown to alter the biomechanical specificities of the stretched muscles. The possible effect over the short and long term upon the sensorial capacities induced by such stretching has not been addressed yet. Fourteen healthy individuals were involved to assess the proprioceptive repercussion and their effects upon postural control strategies. Postural control and proprioceptive assessment were measured twice: when receiving sport shoes inducing ankle dorsiflexion and 18 days later. Proprioceptive effects were assessed using an ad-hoc device through which the seated and blindfolded subjects were required to reposition their feet in a starting position after the ankles were passively displaced to dorsiflexed and plantarflexed positions. Center-of-gravity horizontal displacements (CG(v)), estimated from center-of-pressure (CP) displacements, and CP-CG(v) displacements were measured through a force platform during upright quiet stance maintenance. The initial session was recorded with the subjects barefoot and wearing the shoes with a set of chocks with 0 degrees (horizontal) and -5 degrees (dorsiflexion) tilting angles. The second session included only barefoot performance in horizontal and dorsiflexion conditions. Dorsiflexion had no immediate effect on the postural control strategies along the anteroposterior axis. In contrast, barefoot or wearing shoes, stability was increased along the mediolateral axis during the dorsiflexion conditions. No ankle proprioceptive or postural change was observed after wearing the shoes for 18 days. Wearing dorsiflexion sport shoes induces short-term effects probably by inducing a backward tilt of the pelvis. A muscular adaptation likely prevents this effect from being prolonged.

Delayed influence of stretch-shortening cycle fatigue on large ankle joint position coded with static positional signals.

This study examines the static position sense from the ankle joint following a unilateral exhaustive stretch-shortening cycle (SSC)-type exercise involving mostly the triceps surae muscle group. Fatigue effects were quantified within the exercised and non-exercised leg through a maximal isometric voluntary plantarflexion test (MVC) performed immediately before (Pre) and after the SSC exercise, and repeated 2 (D2) and 8 (D8) days later. The static position sense test consisted in active reproductions with the non-exercised ankle of two target dorsiflexed positions (small and large) previously maintained with either the non-exercised (control procedure) or the exercised ankle (fatigue procedure). This test was carried out at Pre, D2, and D8. At D2, the MVC test revealed significant decreases in voluntary soleus muscle activity and peak plantarflexion force. The position sense test showed no error in reproduction accuracy in the control procedure. In contrast, the fatigue procedure revealed an overestimation of the large dorsiflexed position, only, with an associated increase of the agonist tibialis muscle activity. In agreement with the antagonist (stretched) muscle influence on the position sense, this overestimation is mostly attributed to potential SSC fatigue effects on ascending proprioceptive afferents issued from the exercised/inflamed antagonist muscles.

Changes in illusory ankle movements induced by tendon vibrations during the delayed recovery phase of stretch-shortening cycle fatigue: an indirect study of muscle spindle sensitivity modifications.

This study examined the perceived movement velocity induced by tendon vibrations during the delayed recovery phase of a stretch-shortening cycle (SSC)-type exercise characterized by 2 to 4 days of neuromuscular and proprioceptive impairments. Seven subjects performed until exhaustion series of unilateral rebounds involving mostly the triceps surae muscle group. Fatigue effects were quantified for the exercised and non-exercised legs through muscle soreness and maximal voluntary plantarflexion test (MVC) performed immediately before (PRE) and after the SSC exercise, and repeated 2 days later (D2). At PRE and D2, mechanical vibrations at 40, 60, 80, 100, and 120 Hz were applied to distal tendons of the exercised ankle. For each vibration, the subjects had to reproduce the perceived movement velocity with the non-exercised ankle. According to previous studies, the sole exercised leg was characterized by a D2 peak of muscle soreness associated, in the MVC test, with significant decreases in maximal force and mean soleus muscle activity. As compared to the PRE test and in all subjects, the vibrations applied at D2 to the tendon of the fatigued ankle extensor muscles led to significant decreases in the perceived movement velocity at 80 and 100 Hz, but to an increased one at 40 Hz. In contrast, vibrations applied to the tendon of the non-fatigued ankle flexor muscle did not result in any significant change. These results suggest that the delayed recovery phase of SSC fatigue is characterized by changes in muscle proprioception, which may partly result from a decreased sensitivity of the primary endings.

Exhaustive stretch-shortening cycle exercise: no contralateral effects on muscle activity in maximal motor performances.

Minor cross-over effects of unilateral muscle fatigue have been reported after isometric exercises. The present study re-examined this possibility after an exhaustive stretch-shortening cycle (SSC)-type exercise. Twenty-five subjects performed on a sledge apparatus a unilateral exhaustive rebound exercise involving mostly the triceps surae muscle group. Ipsilateral vs contralateral fatigue effects were compared in uni- and bilateral tests that included a maximal isometric voluntary contraction (MVC) and a series of 10 maximal drop jumps (DJ). These tests were carried out just before and after (POST) the exhaustive SSC exercise, and were repeated 2 days later (D2), at the expected time of major inflammation and pain. The exercised (fatigued) leg analysis revealed significant declines in MVC and DJ performances at POST and D2, the latter ones being associated with significant decreases in voluntary muscle activity. In contrast, no significant change was found for the non-fatigued leg. These results do not support the existence of cross-over effects after exhaustive SSC exercise, at least when tested in maximal static and dynamic unilateral motor tasks.