Background: Previous studies show that people with lower limb amputation (LLA) have a sedentary lifestyle, reduced walking capacity, and low cardiorespiratory fitness (VO 2 peak). There is, however, no knowledge on the relationship between cardiorespiratory fitness and objectively measured level of physical activity in daily life. Objectives: To investigate the relationship between upper-body VO 2 peak, physical activity levels, and walking capacity in persons with LLA.Study design: Correlational and descriptive study. Methods: Fourteen participants with LLA performed an assessment of VO 2 peak on an arm-crank ergometer and walking capacity (preferred walking speed and 2-minute walking test). Level of physical activity was measured over 7 days with a step activity monitor (number of steps; sedentary time; and proportion of low-intensity, moderate-intensity, high-intensity, and peak-intensity activity level). Results: VO 2 peak correlated significantly with number of steps per day (r 5 0.696, p 5 0.006), sedentary time (r 5 20.618, p 5 0.019), high-intensity activity level (r 5 0.769, p 5 0.001), and peak-intensity activity level (r 5 0.674, p 5 0.008). After correcting for age, correlations were still large and significant. Large correlations were also found between VO 2 peak, preferred walking speed (r 5 0.586, p 5 0.027), and 2-minute walking test (r 5 0.649, p 5 0.012). Conclusions: We provide the first evidence of the strong relationships between upper-body VO 2 peak, sedentary behavior, highintensity activity level, and walking capacity in persons with LLA. Further research is needed to investigate the potential effect of upperbody cardiorespiratory fitness on the level of activity in daily life, or vice versa.

Background: This study investigated the impact of COVID-19 restrictions on ambulatory activity and health-related quality of life (HR-QoL) in people with a lower limb amputation (LLA) in Norway. We hypothesized that the restrictions would negatively affect HR-QoL and decrease prosthetic wear time and ambulatory activity in participants with already limited mobility. Methods: Twenty individuals with LLA (age and time since amputation 56.2 6 11.9 and 22.3 6 20.1 years, respectively) participated. Ambulatory activity (stepwatch: prosthetic wear time; steps per day; minutes of low-intensity (1-15 steps min -1 ), moderate-intensity (16-40 steps min -1 ), and high-intensity ambulation (.40 steps min -1 )) and HR-QoL (EQ-5D-5L) data were collected prepandemic and 8-12 months later during pandemic restrictions. Semistructured interviews identified personal experiences of coping with restrictions. Results: Prosthetic wear time decreased significantly (21.0 6 1.5 hours day -1 , p , 0.05). Steps per day (440 6 1481), moderateintensity and high-intensity ambulation (3.7 6 23.4, and 4.8 6 13.9 minutes day -1 , respectively), and EQ-5D-5L index (.02 6 .10) increased, whereas low-intensity ambulation decreased (21.5 6 16.1 minutes day -1 ), all nonsignificant changes. Qualitative analysis identified three themes related to coping with restrictions: (1) personal situation, (2) a prosthetic user's perspective, and (3) mindset. Conclusions: Increased time spent at home might explain the decreased prosthetic wear time. Contrary to the hypothesis, participants did not decrease their physical activity, and the declined low-intensity ambulation was offset by increased moderateintensity and high-intensity ambulation. A positive mindset, intrinsic motivation, and health awareness may be important factors for maintaining ambulatory activity and HR-QoL in people with LLA.

Background: The rapidly increasing use of wearable technology to monitor free-living ambulatory behavior demands to address to what extent the chosen outcome measures are representative for real-world situations. This scoping review aims to provide an overview of the purpose of use of wearable activity monitors in people with a Lower Limb Amputation (LLA) in the real world, to identify the reported outcome measures, and to evaluate to what extent the reported outcome measures capture essential information from real-world ambulation of people with LLA. Methods: The literature search included a search in three databases (MEDLINE, CINAHL, and EMBASE) for articles published between January 1999 and January 2022, and a hand-search. Results and conclusions: 98 articles met the inclusion criteria. According to the included studies’ main objective, the articles were classified into observational (n = 46), interventional (n = 34), algorithm/method development (n = 12), and validity/feasibility studies (n = 6). Reported outcome measures were grouped into eight categories: step count (reported in 73% of the articles), intensity of activity/fitness (31%), type of activity/body posture (27%), commercial scores (15%), prosthetic use and fit (11%), gait quality (7%), GPS (5%), and accuracy (4%). We argue that researchers should be more careful with choosing reliable outcome measures, in particular, regarding the frequently used category step count. However, the contemporary technology is limited in providing a comprehensive picture of real-world ambulation. The novel knowledge from this review should encourage researchers and developers to engage in debating and defining the framework of ecological validity in rehabilitation sciences, and how this framework can be utilized in the development of wearable technologies and future studies of real-world ambulation in people with LLA.

Purpose: To compare the effects of test protocols with different increments in workload and duration on peak oxygen uptake (V ̇O2peak), and related physiological parameters during seated upper-body poling (UBP). Methods:Thirteen upper-body trained, male individuals completed four UBP test protocols with increments in workload until volitional exhaustion in a counterbalanced order: 20W increase/every 30s, 20W/60s, 10W/30s and 10W/60s. Cardio-respiratory parameters and power output were measured throughout the duration of each test. Peak blood lactate concentration (bLapeak) was measured after each test. Results: The mixed model analysis revealed no overall effect of test protocol on V ̇O2peak , peak minute ventilation (VEpeak), peak heart rate (HRpeak), bLapeak, (all p ≥0.350), whereas an overall effect of test protocol was found on peak power output (POpeak), (p=0.0001), respiratory exchange ratio (RER) (p=0.024) and test duration (p<0.001). There was no difference in POpeak between the 20W/60s (175±25W) and 10W/30s test (169±27W; p=0.092), whereas POpeak was lower in the 10W/60s test (152±21W) and higher in the 20W/30s test (189±30W) compared to the other tests, (all p=0.001). In addition, RER was 9.9% higher in the 20W/30s-compared to the 10W/60s test protocol, (p=0.003). Conclusions: The UBP test protocols with different increments in workload and duration did not influence V ̇O2peak and can therefore be used interchangeably when V ̇O2peak is the primary outcome. However, POpeak and RER depend upon the test protocol applied and the UBP test protocols can therefore not be used interchangeably when the latter are primary outcome parameters. Keywords; upper-body exercise, exercise test protocol, aerobic capacity Abbreviations ACEarm-crank ergometry bLapeakpeak blood lactate HRpeakpeak heart rate POpeakpeak power output RERrespiratory exchange ratio RPEratings of perceived exertion UBP-upper-body poling V ̇CO2carbon dioxide production VEminute ventilation V ̇O2peakpeak oxygen uptake Wwatt Compliance with ethical standardsAll procedures in the present study are in accordance with the ethical standards of the Helsinki declaration. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.