amputation is the surgical removal of an external part of the body , most often a limb or a 
 part of it , as a form of treatment1 . 

amputation not only requires additional funds for rehabilitation , but also prosthetic 
 creation , management and maintenance2 . 

compared to normal ambulation , the energy costs for prosthetic ambulation are much higher 
 increased energy .
the energy required for ambulation in lower extremity amputees are as 
 follows : unilateral trans - tibial amputation 4060% , unilateral trans - femoral amputation 90 
 to 120% , bilateral trans - tibial amputation 60100% and bilateral trans - femoral amputation 
 > 200% above the normal and this energy demand becomes even higher if additional 
 significant comorbidities exist3 . 

generally , patients with trans - tibial amputation , whether unilateral or bilateral , cope 
 better than those who undergo above - knee amputation .
rehabilitation of a patient who has undergone 
 amputation is an intricate process , as several factors determine successful ambulation with 
 a limb prosthesis .
these factors include pre - existing pulmonary disease , cardiovascular 
 disease , peripheral vascular disease , diabetes , hypertension , hyperlipidemia , the status of 
 the other limb and functional level prior to amputation3 .
the aim of this study was to investigate the effect of segmental weight of the prosthesis 
 on hemodynamic responses and energy expenditure in lower extremity amputees .
it is known 
 that with the ankle attachment , that the articifial foot prosthetics weight could differ . 

therefore , the following hypotheses were formed for this research study : 1 ) the segmental 
 weight changes of prosthesis have a significant effect on the hemodynamic responses and 
 energy expenditure of lower limb amputees and 2 ) when the segmental weight is increased the 
 hemodynamic responses and energy expenditure of lower limb amputees are increased .
the subjects were patients who 
 had undergone lower limb amputation and who had been referred to the prosthetics unit of the 
 department of physiotherapy and rehabilitation of hacettepe university for a new prosthesis 
 to be designed or the current prosthesis to be repaired as well as for evaluation for the 
 physiotherapy and rehabilitation programme .
a total of 13 lower limb amputees aged 18 to 
 65  years who had undergone unilateral syme s ( 1 patient ) , transtibial ( 11 patients ) or 
 transfemoral ( 1 patient ) amputation and were able to walk independently , had no need for 
 assistance and volunteered to participate were included in this study .
exclusion criteria were age below 18  years or above 
 65  years , hypertension , bilateral lower limb amputation , wheelchair or other aid use , 
 cardiac and pulmonary disorders , and lack of cooperation .
one subject was excluded due to 
 severe lower limb pain while walking . with the ankle attachment , it is determined that the 
 lightest articifial foot prosthetics was 430  g and the heaviest was 680  g. the difference 
 between the weight of the lightest and the heaviest prosthesis used was 250  g. thus , 250  g 
 was used as the segmental weight .
all the patients completed the measurements first without 
 weight and then with a 250  g weight placed on the ankle of the prosthesis . all subjects were 
 informed about the study and written consent was obtained .
hacettepe university 
 noninterventional clinical researchs ethics committee approved the study ( go 14/33 ) and the 
 study took place between february 2014 and july 2014 .
the following methods , evaluations and procedures were used for this study : 1 ) general 
 evaluation : general information and medical background data of the subjects were collected 
 by means of an interview as well as from their medical files .
name , age , the age of 
 amputation , level of amputation , years of prosthesis use were recorded .
2 ) blood pressure : 
 the blood pressure in terms of systolic pressure ( sbp ) and diastolic pressure ( dbp ) was 
 measured with a sphygmomanometer before and after functional performance tests , with and 
 without the study weight4 .
3 ) heart rate : 
 the heart rate was determined with the radial pulse method by placing the index and middle 
 fingers on the correct spot to feel the pulse and counting the number of beats per minute . 

the heart rate of all subjects was counted before and after the functional performance 
 tests , with and without the study weight4 . 

double product of the patients were determined by consisting of the systolic blood pressure 
 ( sbp ) multiplied by the pulse rate ( pr ) , is an index of myocardial oxygen consumption4 .
4 ) energy expenditure evaluation : the 
 easy - to - use physiological cost index [ ( walking heart rate )  ( resting heart rate ) / ( walking 
 speed ) ] was used to determine energy expenditure .
the patient was asked to sit on a chair 
 for 10 minutes before starting the 6 minute walk test ( 6mwt ) and the heart rate was 
 determined .
the patient was asked to sit 
 on the chair again at the end of 6 minutes and the heart rate was measured again .
after the 
 patient had rest for 15 minutes again , the patient repeated the 6mwt , this time with added 
 weight .
once all the parameters were ready , the physiological cost index indicating the 
 energy expenditure was calculated separately for with and without the study weight for a 
 possible comparison5 .
5 ) functional 
 performance tests : six - minute walk test ( 6mwt ) : 6mwt is used to measure 
 functional capacity , walking distance ability and endurance6 .
the distance of the 6mwt reflects whether a person could 
 practically ambulate in the community .
the reliability of the 6mwt has been established for 
 lower extremity amputees with a test - retest reliability greater than 0.97 .
a start and end line was indicated for each 60  m lap and 
 turnaround points were marked on the floor using colored tape .
the participant was asked to 
 walk straightly as far as possible for six minutes in the demarcated corridor and to turn 
 back at the end of each lap .
the participant was informed to stop before the test was finished if he / she felt 
 uncomfortable and was unable to complete the full six minutes . in such cases ,
the test was 
 terminated and repeated later on . at the end of test , the total distance was measured in 
 meters and recorded .
the patient sat on the chair near the starting point and the blood 
 pressure and heart rate were measured .
the subject was given an opportunity to rest for 10 
 minutes before the next test was started .
10 stairs up & down test : the ten stairs up & down test is 
 usually used to strengthen the lower extremity muscles and improve the balance of lower limb 
 amputees8 . before the test ,
a trial was 
 performed to make sure that the subjects could complete the test .
timing began on the signal to start and 
 ended when the participant returned to the ground level with both feet .
we first asked the 
 subjects to go up & down 10 stairs , without the weight .
we started the stopwatch when 
 the subject started to ascend the stairs and stopped it when the descent was completed . the 
 blood pressure and heart rate were recorded .
after ten minutes of rest time , the test was 
 repeated with the 250  g added weight .
all demographic as well as dependent variables 
 are presented by mean values , standard deviation ( sd ) and minimal and maximal values . 

the 6mwt distance , ten - stairs up & 
 down test duration with and without weight were compared .
the same comparison was performed 
 for the blood pressure and heart rate before and after , 6mwt , the ten - stairs up & down 
 test with and without weight .
the homogeneity of all variables was 
 determined with the kolmogorov - smirnov test , a nonparametric test .
the paired samples t - test 
 was used because of the homogeneity of the parameters .
analysis within the dependent 
 variables was also performed to show any differences in the variables with and without 
 weight and before and after the 6mwt and ten stairs up & down test .
similarly , the 
 paired sample t - test was used for normally distributed data .
the significance level was set 
 at the p<0.05 level with p<0.01 showing strong significance .
a total of 13 patients with a mean age of 44.00  15.85  years ( min=18max=65  years ) were 
 included in the study .
year of 
 the prosthetics use was 15.62  14.16  years ( min=1max=42  years ) .
the distance walked in 6mwt and the duration in 10 stairs up & down tests , with weight 
 and without weight was compared and presented in table 
 1table 1.the comparison of 
 distance and duration in functional performance tests without weight and with 
 weightfunctional performance tests ( n=13)mean  sdminimummaximumt6mwt without weight ( m)380.0  79.8219.0542.53.346 * 6mwt with weight ( m)365.1  82.3218.0533.310 stairs up & down without weight 
 ( sec)17.6  6.810.031.00.67010 stairs up & down without weight ( sec)17.9  6.89.030.0n : number of patients ; 6mwt : 6 
 minute walk test ; sd : standard deviation ; m : meter , sec : second , * statistically 
 significant , p<0.05 .
there was significant 
 difference between the distance covered by subjects without weight and with weight ( t=3.346 , 
 p=0.006 ) .
n : number of patients ; 6mwt : 6 
 minute walk test ; sd : standard deviation ; m : meter , sec : second , * statistically 
 significant , p<0.05 hemodynamic responses of the patients for 6mwt and 10-stairs up & down without weight 
 and with weight before the tests and after the tests are presented in tables 2table 
 2.comparison of hemodynamic responses for 
 6mwt6mwtb ( n=13)mean  sdmean diff  sd 
 hr ( bpm)beforewithout 
 weight75.0  8.71.5  3.6with 
 weight77.7  10.1afterwithout 
 weight80.9  9.03.1  4.5with 
 weight83.9  8.9 sbp ( mmhg)beforewithout weight116.5  12.00.4  
 3.8with weight116.2  11.9afterwithout weight116.0 
  11.21.9  3.3with weight117.7  
 12.4dbp ( mmhg)beforewithout weight76.5  8.81.5  
 5.6with weight75.0  8.7afterwithout weight74.6 
  8.80.0  2.0with weight74.6  
 9.0dp ( mmhg.bpm)beforewithout weight8,600.0  1,540.5157.7  472.6with weight8,757.7  1,650.4afterwithout 
 weight9,406.2  1,683.1508.5  589.1with weight9,914.6  
 1,750.66mwt : 6 minute walk test ; n : 
 number of patients ; sd : standard deviation ; mean diff : mean difference ; hr : heart 
 rate ; bpm : beats per minute ; sbp : systolic blood pressure ; dbp : diastolic blood 
 pressure ; dp : double product ; mmhg : millimeters of mercury , * statistically 
 significant , p<0.05 and 3table 
 3.comparison of hemodynamic responses for 10 stairs up and 
 down10 
 stairs up & down ( n=13)mean  sdmean diff  sd hr ( bpm)beforewithout weight69.1  15.48.3  

18.9with weight77.4  9.5afterwithout 
 weight80.9  8.83.6  4.2*with weight84.5  
 8.7 sbp ( mmhg)beforewithout weight115.4  12.21.2  
 3.0with weight116.5  13.1afterwithout 
 weight115.4  12.23.1  5.6with weight118.5  
 13.5dbp ( mmhg)b eforewithout weight76.5  9.40.4  

1.4with weight76.2  9.8afterwithout 
 weight75.5  9.10.6  2.2with weight76.2  
 9.8dp ( mmhg.bpm)beforewithout weight7,994.2  2,173.21,072.3  2,513.5with weight9,066.5  
 1,777.8afterwithout weight1,629.0  451.8297.7 
856.7with 
 weight1,777.8  
 493.1sd : standard deviation ; n : number of 
 patients ; mean diff : mean difference ; hr : heart rate ; bpm : beats per minute ; sbp : 
 systolic blood pressure ; dbp : diastolic blood pressure ; dp : double product ; mmhg : 
 millimeters of mercury , * statistically significant , 
 p<0.05 .
the only significant difference was between 
 the heart rate values and double product after 6mwt ( t=2.446 , p=0.031 ) ( t=3.112 , p=0.009 ) 
 and the heart rate values after 10-stairs up & down test , with and without weight 
 ( t=3.138 , p=0.009 ) . the results for sbd and dbp did not show any significant 
 difference .
6mwt : 6 minute walk test ; n : 
 number of patients ; sd : standard deviation ; mean diff : mean difference ; hr : heart 
 rate ; bpm : beats per minute ; sbp : systolic blood pressure ; dbp : diastolic blood 
 pressure ; dp : double product ; mmhg : millimeters of mercury , * statistically 
 significant , p<0.05 sd : standard deviation ;
n : number of 
 patients ; mean diff : mean difference ; hr : heart rate ; bpm : beats per minute ; sbp : 
 systolic blood pressure ; dbp : diastolic blood pressure ; dp : double product ; mmhg : 
 millimeters of mercury , * statistically significant , 
 p<0.05 in addition , comparison of hemodynamic responses were made between before and after 6mwt 
 for non - weight as well as between before and after for with weight .
the results indicated 
 that only heart rate showed significance for before - after comparison without weight 
 ( t=4.854 , p=0.000 ) and before - after comparison with weight ( t=4.757 , p=0.000 ) .
comparison of 
 hemodynamic responses were made between before and after 10 stairs up & down for 
 non - weight as well as between before and after for with weight .
the results indicated that 
 only heart rate showed significance for before - after comparison without weight ( t=2.525 , 
 p=0.027 ) and before - after comparison with weight ( t=5.095 , p=0.000 ) .
the difference between the physiological 
 cost index of the patients with and without weight also showed significance ( t=2.342 , 
 p=0.037 ) ( table 4table 4.physiological cost index of patients without 
 weight and with weight paired samples testpci ( pulse / m)mean  sdmean diff  sd 
 without weight79.6  8.82.9  4.5*with weight82.6  8.6pci : 
 physiological cost index ; pulse / m : pulse per minute ; sd : standard deviation ; mean 
 diff : mean difference ; hr : heart rate ; sbp : systolic blood pressure ; dbp : diastolic 
 blood pressure , * statistically significant , 
 p<0.05 ) .
pci : 
 physiological cost index ; pulse / m : pulse per minute ; sd : standard deviation ; mean 
 diff : mean difference ; hr : heart rate ; sbp : systolic blood pressure ; dbp : diastolic 
 blood pressure , * statistically significant , 
 p<0.05
this study indicated that the weight of the prosthesis makes a significant difference on 
 the heart rate and energy expenditure but not affect the blood pressure during the 
 functional performance tests .
a total of 13 subjects completed our study that was based on the hypothesis that the weight 
 of the prosthesis has an effect on the hemodynamic responses of lower limb amputees .
most 
 similar studies discuss the effect of the added prosthesis mass on the kinematic and kinetic 
 features of the gait cycle , oxygen and energy consumption . some of these studies have also 
 discussed the effect of weight and exercises on the heart rate and the stride and step 
 lengths of lower limb amputees , but these studies provided no information on the systolic 
 and diastolic pressures9,10,11,12,13,14,15 .
the power 
 analysis of our study revealed that 13 unilateral lower limb amputees would be adequate . 

three of the 13 
 subjects were able to go the same distance as without the added weight .
nine suffered a 
 limitation of their walking distance when the weight was added to their prosthetic limb .
one 
 subject even went further when the weight was added to the prosthetic limb .
a previous study have reported no 
 significant change between gait parameters such as stride and step lengths and stance and 
 swing phase durations in both the prosthetic and intact extremities with alteration of the 
 prosthetic mass16 . although there have 
 been studies comparing the effects of the prosthetic mass on oxygen consumption and gait 
 efficiency , our study aimed to focus on hemodynamic responses of the patients with and 
 without extra weight .
lin - chan17 used prostheses with 3 
 different masses ( 100% , 80% and 60% ) and found that the prosthetic mass did not 
 significantly change oxygen consumption or gait efficiency , although the relative exercise 
 intensity significantly increased while stride frequency decreased with the 60% and 100% 
 conditions , hillery et al.18 examined 
 gait kinematics of patients with transfemoral amputation by adding 1.460  kg to the distal 
 foot portion of the prosthesis and the stride frequency showed a small decrease18 .
gitter et al.19 investigated the effects of adding masses of 0.68 and 
 1.34  kg to the center of mass of the prosthesis of 10 subjects with trans femoral amputation 
 and they found no significant difference in stride length or frequency between the different 
 masses .
czerniecki and colleagues20 
 studied the effect of different prosthetic masses by attaching 68  g and 1.34  kg to the 
 center of mass at four different walking speeds in eight patients with transfemoral 
 amputation .
their study showed no significant difference between the mass conditions at four 
 different walking speeds as well as no difference in the kinematic and kinetic 
 characteristics of gait when steel components were replaced with titanium .
the hypothesis of 
 another study was that a heavier prosthesis required more muscle activity to decelerate 
 during the last part of swing phase and the authors found no difference in knee angle when 
 titanium and steel trials were compared13 .
we did not find any significant statistical difference in systolic and diastolic blood 
 pressures of the subjects under different conditions .
there was some difference in the blood 
 pressure of some subjects but this was not statistically significant .
we can therefore 
 conclude that the prosthetic weight does not have an effect on the blood pressure of lower 
 limb amputees for our study .
there are just few studies that describe the effect of exercise 
 and prosthetic weight on the hemodynamic responses of the lower amputees .
our results was 
 similar to lin and bose study , reported no difference in blood pressure before and after 
 6mwt7 .
hinton et al.21 investigated the 
 hemodynamic responses with ortho crutches and axillary crutches and found no significant 
 difference between mean systolic and diastolic blood pressure between the two .
the mean 
 systolic blood pressure with unassisted ambulation was lower than with ortho crutches and 
 axillary crutches
. all our subjects could walk independently and did not use crutches and we 
 found no difference in blood pressure before and after non - weight and with weight 
 conditions .
provencher et al.22 reported that 6mwt 
 increased the heart rate of the patients in their study .
vestering et al.23 similarly found that the combined 
 ergometer test increased the heart rate of lower limb amputees .
we found that the heart rate 
 was increased in all our tests indicating that both exercise and addition of weight 
 increases the heart rate .
another study reported that the weight used has an effect on the 
 heart rate in a study using three different mass conditions on subjects with transtibial 
 amputation and found that the 100% condition increased the heart rate of the subject17 .
lenka et al.24 added four different 
 weights ( 200  g , 400  g , 600  g and 800  g ) to the lower limb amputees prosthetic ankles and 
 found increased heart rates with increasing weights .
this result is similar to ours , 
 indicating that the prosthetic weight influences the heart rate with increased heart rate 
 with increased weight while walking and during the 10-step stair climb test .
sokhangoei et 
 al.25 compared the heart rates of an 
 amputee group and control group and reported that the energy consumption amount and heart 
 activity at any speed were higher in the amputee group .
the heart rate of amputees was noted 
 at different speeds and increasing speed was found to increase the heart rate .
our study 
 showed similarity with sokhangoei in terms of significance in heart rate and energy 
 consumption .
however , we did not have any control groups to compare the energy expenditure 
 difference between amputees and healthy individuals .
our study has proven that weight addition increased the heart rate during tests where the 
 muscles need and use more oxygen and glucose from the blood .
thus , the heart delivers blood to the lungs and 
 kidneys more quickly so that these organs can remove the waste from the body .
the faster the 
 muscles use energy and create waste , the faster the heart must pump the blood . as the 
 patients induces greater metabolic demands for maintenance of balance and posture and for 
 performing the functional performances .
shiomi had five healthy men perform the stair climb test and determined that the heart rate 
 was increased afterwards with a statistically significant difference26 .
we compared the heart rate before and after the test , 
 first without adding a weight and then with the weight , and found a significant difference 
 in the heart rate in both conditions .
the weight increased the heart rate of amputees 
 performing the 6mwt and 10-step stair climb tests .
we needed a sample of at least 13 subjects for this study but a larger sample might have 
 been more informative .
one limitation of the study is that we did not distribute the 
 amputees into groups according to the level of amputation and compare the results 
 accordingly due to limited number of participants from each level .
in addition , we only 
 added 250  g to the prosthesis and the effects of different weights on the hemodynamic 
 response of amputees needs to be investigated .
we conclude that the segmental weight of the prosthetic limb has an significant effect on 
 the heart rate and energy expenditure but has no effect on the systolic and diastolic blood 
 pressure of lower limb amputees . when the segmental weight is increased the heart rate and 
 energy expenditure of lower limb amputees are increased .
the distances during the six - minute 
 walk test were decreased with the weight .
examination of various factors such as age , 
 exercise capacity , years of wearing a prosthesis , strength of lower limbs is also necessary . 
 in order to generalize our results to lower limb amputees , more patients need to be included 
 in future studies .
the weight of the prosthesis and comparison with the unaffected / healthy 
 lower extremity should be considered in the rehabilitation of amputees .
the paper is the original work of the authors and not copied from any other work .
no funding or grants or equipment provided for the project from any source ; no financial 
 benefits to the authors .
the paper is the original work of the authors and not copied from any other work .
no funding or grants or equipment provided for the project from any source ; no financial 
 benefits to the authors .
 [ purpose ] the aim of this study was to investigate the effect of segmental weight of the 
 prosthesis on hemodynamic responses and energy expenditure in lower extremity amputees . 
 [ subjects and methods ] thirteen patients with a mean age of 44  15.84  years and with 
 unilateral transtibial , transfemoral and syme s amputation were included to the study . 
 the 
 difference between the lightest and the heaviest prosthesis , 250  g used as the weight . 
 all 
 the patients completed the measurements first without weight and then with 250  g weight on 
 the ankle joint . 
 the blood pressure and heart rate of the patients were recorded before 
 and after six minute walk test ( 6mwt ) and 10 stairs up & down stairs test . 
 
 physiological cost index was used to calculate the energy expenditure . 
 [ results ] heart 
 rate and energy expenditure increased significantly when without weight and with weight 
 results compared . 
 [ conclusion ] we conclude that the segmental weight of the prosthetic 
 limb has a significant effect on the heart rate and energy expenditure but has no effect 
 on the systolic and diastolic blood pressure of lower limb amputees . in order to 
 generalize our results to lower limb amputees , more patients need to be included in future 
 studies . 
INTRODUCTION
SUBJECTS AND METHODS
RESULTS
DISCUSSION
Disclosure
Conflict of interest