Does body posture during tree felling influence the physiological load of a chainsaw operator?

Abstract

Does body posture during tree felling influence the physiological load of a chainsaw operator? Ann Agric Environ Med. 2017; 24(3): 401-405. doi: 10.5604/12321966.1235177 Abstract Introduction and Objectives. Holding determined body postures during work is connected with muscles activity. The more forced the posture, the larger the number of muscles taking an active part in holding and stabilizing the work posture. During logging, the greatest share of awkward (forced) working postures occurs in tree felling by chainsaw. Materials and Method. A group of 10 experienced fellers aged 47.5±7.3 (37 -59-years-old) was studied. Heart rate (HR) was measured during simulation of felling activity in 4 working postures: back bent forward with straight legs (stoop), back bent forward with bent legs (flexed-stoop), squat and kneeling on one knee (half-kneel). Results. The lowest value of HR was noticed for squatting -114.1 bpm, then for kneeling on one knee -116.3 bpm. HR during felling in a standing posture with straight legs amounted to 121.5 bpm and for standing with bent legs 125.3 bpm. For all studied postures the differences in average HR values were statistically significant at p<0.01. Conclusions. A working posture during tree felling by chainsaw has influence on the level of physiological workload of an operator. Standing bent forward body postures cause higher heart response than squatting and half-kneeling.

Assessing the Impact of Work Activities on the Physiological Load in a Sample of Loggers in Sicily (Italy)

“…Furthermore, investigating the time spent in awkward postures allowed the researchers to observe that a higher cardiac cost during the felling activities was correlated with a trunk inclination greater than 60 • . These findings agree with previous studies that demonstrated the correlation between awkward posture and cardiac cost [6].…”

“…The average HR values measured in our study during felling, delimbing, and bucking were, respectively 136.7 bpm, 143.5 bpm, and 135.63 bpm. These HR results were slightly higher than those observed in Turkey by Grzywinski et al, who registered average values of heart rate during felling between 114.1 and 125.2 bpm among ten loggers using a chainsaw of 7.5 kg (average chainsaw weight in our study was 7.39 kg) [6]. Moreover, Grzywinski reported the highest cardiovascular response during the felling task, while our data showed higher values during the delimbing activities.…”

“…Additionally, the literature indicates that high levels of physiological workload among chainsaw operators are associated with awkward body postures during the activity. Most notably, the literature indicates that the highest cardiovascular responses were associated with felling tasks that often require loggers to work in postures involving moderate to severe trunk and knee flexion [6]. Therefore, attention to body mechanics is fundamental to work design interventions aimed at reducing the physiological effort of professional loggers.…”

The Impact of Body Posture on Heart Rate Strain during Tree Felling

“…Another problem is the frequent adoption of bad body postures during chainsaw operation, a multifactorial issue [ 27 ] that unites topographic features, type and size of equipment, previous vocational training record, and anthropometric features to frequently arrive at the rather simplistic yet at the same time deeply rooted in forestry practice saying that “no two trees can be harvested in the same way”. In short, a wide variability of working postures can be identified in forest operations [ 2 , 28 ].…”

“…Working muscles need appropriate amounts of oxygen and energy substrates delivered by the circulatory system [ 29 ]. Thus, postures that require a greater involvement of muscles are characterized by a greater physiological strain [ 28 , 30 ]. Epidemiological studies have shown that the interactions between inappropriate postures and movements, high forces, and high repetition rates can give rise to musculoskeletal disorders of various severities [ 31 ].…”