Previous research has shown that walkers provided with interactive simulations of footstep sounds... more Previous research has shown that walkers provided with interactive simulations of footstep sounds on a surface material different from the one they are walking upon, experience pseudo-haptic illusions and adjust their walking kinematic according to the perceived surfaces' compliance. Since walking on real grounds with different degrees of compliance leads to different metabolic costs, an open question is whether pseudo-haptic illusions created by interactive footstep sounds are able to affect the metabolic parameters. This study investigated whether metabolic cost and movement's kinematics are affected by such interactive auditory feedback in a constrained condition as walking on a treadmill. Participants were walking on a treadmill under three listening conditions: actual footsteps sounds, interactive simulations of footstep sounds on gravel and snow. The metabolic and kinematic data, as well as the perceived exertion, sense of effort, easiness, and feeling of sinking were recorded. Results showed that interactive footstep sounds provided during treadmill walking did not affect kine-matic and metabolic parameters of walking, while they were effective in modulating participants' perception. These results suggest that in a constrained and non self-selected pattern of locomotion the sound of action, even though correctly perceived, is not strong enough to induce a change in the metabolic and kinematics of the locomotion.
In this study, we examined the mechanics and energetics of locomotion with a paddle-wheel boat an... more In this study, we examined the mechanics and energetics of locomotion with a paddle-wheel boat and a water bike. Power output (Wtot) was measured directly on the water bike by means of an instrumented chain-ring. The simultaneous assessment of oxygen uptake (VO2) allowed the computation of the "overall" efficiency of locomotion (etao = Wtot/VO2). Mean etao was 0.27 (s = 0.02), which was unaffected by the speed, and was assumed to be the same for the two boats as both are semi-recumbent bicycles. For the paddle-wheel boat, Wtot was then obtained from etao and measures of VO2. The power to overcome (passive) drag was calculated as Wd = D x v (where D is the force measured by means of a load cell when towing the boats at given speeds). Propelling efficiency was calculated as etap = Wd/Wtot, which was lower with the paddle-wheel boat (mean 0.35, s = 0.01) than with the water bike (mean 0.57, s = 0.01). The observed differences in etap and Wd explain why at the highest speed tested (approximately 3 m s(-1), the energy required to cover a unit distance with the water bike is similar to that required to move the paddle-wheel boat at 1.3 m s-1).
The aim of the present study was to quantify the improvements in the economy and efficiency of su... more The aim of the present study was to quantify the improvements in the economy and efficiency of surface swimming brought about by the use of fins over a range of speeds (v) that could be sustained aerobically. At comparable speeds, the energy cost (C) when swimming with fins was about 40 % lower than when swimming without them; when compared at the same metabolic power, the decrease in C allowed an increase in v of about 0.2 ms(-1). Fins only slightly decrease the amplitude of the kick (by about 10 %) but cause a large reduction (about 40 %) in the kick frequency. The decrease in kick frequency leads to a parallel decrease of the internal work rate ((int), about 75 % at comparable speeds) and of the power wasted to impart kinetic energy to the water ((k), about 40 %). These two components of total power expenditure were calculated from video analysis ((int)) and from measurements of Froude efficiency ((k)). Froude efficiency (eta(F)) was calculated by computing the speed of the bendi...
Undersea & hyperbaric medicine : journal of the Undersea and Hyperbaric Medical Society, Inc
Propulsion in water requires a propulsive force to overcome drag. Male subjects were measured for... more Propulsion in water requires a propulsive force to overcome drag. Male subjects were measured for cycle frequency, energy cost and drag (D) as a function of velocity (V), up to maximal V, for fin and front crawl swimming, kayaking and rowing. The locomotion with the largest propulsive arms and longest hulls traveled the greatest distance per cycle (d/c) and reached higher maximal V. D while locomotoring increased as a function of V, with lower levels for kayaking and rowing at lower Vs. For Vs below 1 m/s, pressure D dominated, while friction D dominated up to 3 m/s, after which wave D dominated total D. Sport training reduced the D, increased d/c, and thus lowered C and increased maximal V. Maximal powers and responses to training were similar in all types of locomotion. To minimize C or maximize V, D has to be minimized by tailoring D type (friction, pressure or wave) to the form of locomotion and velocity.
The maximal explosive power of the lower limbs of one astronaut has been measured before launch, ... more The maximal explosive power of the lower limbs of one astronaut has been measured before launch, and 2, 6 and 11 days after re-entry from 31 days on the MIR Station (EUROMIR '94). The subject, sitting on the carriage-seat of a Multipurpose Ergometer-Dynamometer (MED) constructed ad hoc in our laboratory, pushed maximally with both feet on two force platforms (knees angle 110 degrees). The carriage was free to move backwards on two rails inclined 20 degrees upwards. The force (F) of the lower limbs and the speed of the carriage (v) were recorded and the instantaneous mechanical power (w) was calculated as w = F * v. The average value of the mechanical power (w max) throughout the explosive effort was then obtained. The overall duration of the push was on the average about 0.3 s. It was observed that, at day R+2, mean force, maximal velocity, maximal power (mean and peak), maximal acceleration and overall mechanical work, were all reduced between 60 and 80% of pre-flight values. However, the recovery was remarkably fast, since all these parameters attained about 90% of pre-flight values by day R+11.
The purpose of this study was to investigate the changes in selected biomechanical variables in 8... more The purpose of this study was to investigate the changes in selected biomechanical variables in 80-m maximal sprint runs while imposing changes in step frequency (SF) and to investigate if these adaptations differ based on gender and training level. A total of 40 athletes (10 elite men and 10 women, 10 intermediate men and 10 women) participated in this study; they were requested to perform 5 trials at maximal running speed (RS): at the self-selected frequency (SFs) and at SF ±15% and ±30%SFs. Contact time (CT) and flight time (FT) as well as step length (SL) decreased with increasing SF, while kvert increased with it. At SFs, kleg was the lowest (a 20% decrease at ±30%SFs), while RS was the largest (a 12% decrease at ±30%SFs). Only small changes (1.5%) in maximal vertical force (Fmax) were observed as a function of SF, but maximum leg spring compression (ΔL) was largest at SFs and decreased by about 25% at ±30%SFs. Significant differences in Fmax, Δy, kleg and kvert were observed as a function of skill and gender (P < 0.001). Our results indicate that RS is optimised at SFs and that, while kvert follows the changes in SF, kleg is lowest at SFs.
Previous research has shown that walkers provided with interactive simulations of footstep sounds... more Previous research has shown that walkers provided with interactive simulations of footstep sounds on a surface material different from the one they are walking upon, experience pseudo-haptic illusions and adjust their walking kinematic according to the perceived surfaces' compliance. Since walking on real grounds with different degrees of compliance leads to different metabolic costs, an open question is whether pseudo-haptic illusions created by interactive footstep sounds are able to affect the metabolic parameters. This study investigated whether metabolic cost and movement's kinematics are affected by such interactive auditory feedback in a constrained condition as walking on a treadmill. Participants were walking on a treadmill under three listening conditions: actual footsteps sounds, interactive simulations of footstep sounds on gravel and snow. The metabolic and kinematic data, as well as the perceived exertion, sense of effort, easiness, and feeling of sinking were recorded. Results showed that interactive footstep sounds provided during treadmill walking did not affect kine-matic and metabolic parameters of walking, while they were effective in modulating participants' perception. These results suggest that in a constrained and non self-selected pattern of locomotion the sound of action, even though correctly perceived, is not strong enough to induce a change in the metabolic and kinematics of the locomotion.
In this study, we examined the mechanics and energetics of locomotion with a paddle-wheel boat an... more In this study, we examined the mechanics and energetics of locomotion with a paddle-wheel boat and a water bike. Power output (Wtot) was measured directly on the water bike by means of an instrumented chain-ring. The simultaneous assessment of oxygen uptake (VO2) allowed the computation of the "overall" efficiency of locomotion (etao = Wtot/VO2). Mean etao was 0.27 (s = 0.02), which was unaffected by the speed, and was assumed to be the same for the two boats as both are semi-recumbent bicycles. For the paddle-wheel boat, Wtot was then obtained from etao and measures of VO2. The power to overcome (passive) drag was calculated as Wd = D x v (where D is the force measured by means of a load cell when towing the boats at given speeds). Propelling efficiency was calculated as etap = Wd/Wtot, which was lower with the paddle-wheel boat (mean 0.35, s = 0.01) than with the water bike (mean 0.57, s = 0.01). The observed differences in etap and Wd explain why at the highest speed tested (approximately 3 m s(-1), the energy required to cover a unit distance with the water bike is similar to that required to move the paddle-wheel boat at 1.3 m s-1).
The aim of the present study was to quantify the improvements in the economy and efficiency of su... more The aim of the present study was to quantify the improvements in the economy and efficiency of surface swimming brought about by the use of fins over a range of speeds (v) that could be sustained aerobically. At comparable speeds, the energy cost (C) when swimming with fins was about 40 % lower than when swimming without them; when compared at the same metabolic power, the decrease in C allowed an increase in v of about 0.2 ms(-1). Fins only slightly decrease the amplitude of the kick (by about 10 %) but cause a large reduction (about 40 %) in the kick frequency. The decrease in kick frequency leads to a parallel decrease of the internal work rate ((int), about 75 % at comparable speeds) and of the power wasted to impart kinetic energy to the water ((k), about 40 %). These two components of total power expenditure were calculated from video analysis ((int)) and from measurements of Froude efficiency ((k)). Froude efficiency (eta(F)) was calculated by computing the speed of the bendi...
Undersea & hyperbaric medicine : journal of the Undersea and Hyperbaric Medical Society, Inc
Propulsion in water requires a propulsive force to overcome drag. Male subjects were measured for... more Propulsion in water requires a propulsive force to overcome drag. Male subjects were measured for cycle frequency, energy cost and drag (D) as a function of velocity (V), up to maximal V, for fin and front crawl swimming, kayaking and rowing. The locomotion with the largest propulsive arms and longest hulls traveled the greatest distance per cycle (d/c) and reached higher maximal V. D while locomotoring increased as a function of V, with lower levels for kayaking and rowing at lower Vs. For Vs below 1 m/s, pressure D dominated, while friction D dominated up to 3 m/s, after which wave D dominated total D. Sport training reduced the D, increased d/c, and thus lowered C and increased maximal V. Maximal powers and responses to training were similar in all types of locomotion. To minimize C or maximize V, D has to be minimized by tailoring D type (friction, pressure or wave) to the form of locomotion and velocity.
The maximal explosive power of the lower limbs of one astronaut has been measured before launch, ... more The maximal explosive power of the lower limbs of one astronaut has been measured before launch, and 2, 6 and 11 days after re-entry from 31 days on the MIR Station (EUROMIR '94). The subject, sitting on the carriage-seat of a Multipurpose Ergometer-Dynamometer (MED) constructed ad hoc in our laboratory, pushed maximally with both feet on two force platforms (knees angle 110 degrees). The carriage was free to move backwards on two rails inclined 20 degrees upwards. The force (F) of the lower limbs and the speed of the carriage (v) were recorded and the instantaneous mechanical power (w) was calculated as w = F * v. The average value of the mechanical power (w max) throughout the explosive effort was then obtained. The overall duration of the push was on the average about 0.3 s. It was observed that, at day R+2, mean force, maximal velocity, maximal power (mean and peak), maximal acceleration and overall mechanical work, were all reduced between 60 and 80% of pre-flight values. However, the recovery was remarkably fast, since all these parameters attained about 90% of pre-flight values by day R+11.
The purpose of this study was to investigate the changes in selected biomechanical variables in 8... more The purpose of this study was to investigate the changes in selected biomechanical variables in 80-m maximal sprint runs while imposing changes in step frequency (SF) and to investigate if these adaptations differ based on gender and training level. A total of 40 athletes (10 elite men and 10 women, 10 intermediate men and 10 women) participated in this study; they were requested to perform 5 trials at maximal running speed (RS): at the self-selected frequency (SFs) and at SF ±15% and ±30%SFs. Contact time (CT) and flight time (FT) as well as step length (SL) decreased with increasing SF, while kvert increased with it. At SFs, kleg was the lowest (a 20% decrease at ±30%SFs), while RS was the largest (a 12% decrease at ±30%SFs). Only small changes (1.5%) in maximal vertical force (Fmax) were observed as a function of SF, but maximum leg spring compression (ΔL) was largest at SFs and decreased by about 25% at ±30%SFs. Significant differences in Fmax, Δy, kleg and kvert were observed as a function of skill and gender (P < 0.001). Our results indicate that RS is optimised at SFs and that, while kvert follows the changes in SF, kleg is lowest at SFs.
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Papers by Paola Zamparo