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Backpack and body-armour ensembles reduce pulmonary function according to the mass carried and its distribution around the thorax

Journal Article


Abstract


  • Introduction: Soldiers carry loads as backpacks, body armour

    and as combined (backpack and body amour) arrangements. Such

    thoracic loading contributes to the existing pulmonary restrictive

    and inertial forces, and may impede ventilation. Therefore, we evaluated

    the impact of thoracic load carriage upon lung function by

    varying both the mass (0–54 kg) and its thoracic distribution.

    Methods: Twelve males (age 24.0 y [SD 4.1], mass 81.6 kg [SD

    9.5], height 1.82 m [SD 0.07]) participated in 12, within-subjects

    treatments, conducted on separate days. These included a control

    condition (clothing only), combined backpack and armour (15, 25,

    35, 41, 54 kg; 75% rear distribution), backpack only (15, 25, 35 kg:

    100% rear distribution) and body armour only (15, 25, 35 kg: 50:50

    distribution). For each condition, pulmonary function was evaluated

    during standing rest, including forced vital capacity (FVC),

    forced expiratory volume in 1 second (FEV1), maximal voluntary

    ventilation (MVV) and inspiratory airway occlusion pressure (p0.1).

    Results: Increasing mass in the combined load arrangement

    significantly reduced both FVC (control: 6.24 L [±0.16]; 15 kg:

    5.88 [±0.14]; 25 kg: 5.62 [±0.16]; 35 kg: 5.40 [±0.17]; 41 kg: 5.60

    [±0.15]; 54 kg: 5.51 [±0.14]; p < 0.05) and FEV1 (control: 4.86

    L [±0.15]; 15 kg: 4.56 [±0.19]; 25 kg: 4.39 [±0.15]; 35 kg: 4.19

    [±0.11]; 41 kg: 4.3 5[±0.18]; 54 kg: 4.35 [±0.18]; p < 0.05). Inspiratory

    occlusion pressure was augmented while carrying 41 kg and

    54 kg (p < 0.01), but there was no impact of mass on either FEV1/FVC

    (%) or MVV (L/min). When the load was distributed to solely the

    body-armour, there was no additional change to pulmonary function

    for any given mass. In contrast, when the load was distributed

    solely to the backpack, the mass-dependant reductions in FVC and

    FEV1 were reduced for the 35-kg treatment (p < 0.05).

    Conclusions: The loaded backpack and body-amour ensemble

    imposed mass-dependant reductions of up to 13.8% on FVC and up

    to 13.4% on FEV1. Redistributing the mass to either the backpack or

    body-amour caused no further reductions to pulmonary function

    for any given load. Importantly, there was no evidence of airway

    obstruction for any of the treatments. However, inspiratory neuromuscular

    drive was elevated when carrying the very heavy loads

    and this may predispose some individuals to respiratory muscle

    fatigue.

UOW Authors


  •   Hingley, Lachlan (external author)
  •   Caldwell, Joanne N. (external author)
  •   Taylor, Nigel A.S.. (external author)
  •   Peoples, Gregory

Publication Date


  • 2017

Citation


  • Hingley, L., Caldwell, J. N., Taylor, N. A.S.. & Peoples, G. E. (2017). Backpack and body-armour ensembles reduce pulmonary function according to the mass carried and its distribution around the thorax. In International Congress on Soldiers' Physical Performance, 28th November - 1st December, Melbourne, Australia. Journal of Science and Medicine in Sport, 20 S76-S76.

Start Page


  • S76

End Page


  • S76

Volume


  • 20

Place Of Publication


  • Australia

Abstract


  • Introduction: Soldiers carry loads as backpacks, body armour

    and as combined (backpack and body amour) arrangements. Such

    thoracic loading contributes to the existing pulmonary restrictive

    and inertial forces, and may impede ventilation. Therefore, we evaluated

    the impact of thoracic load carriage upon lung function by

    varying both the mass (0–54 kg) and its thoracic distribution.

    Methods: Twelve males (age 24.0 y [SD 4.1], mass 81.6 kg [SD

    9.5], height 1.82 m [SD 0.07]) participated in 12, within-subjects

    treatments, conducted on separate days. These included a control

    condition (clothing only), combined backpack and armour (15, 25,

    35, 41, 54 kg; 75% rear distribution), backpack only (15, 25, 35 kg:

    100% rear distribution) and body armour only (15, 25, 35 kg: 50:50

    distribution). For each condition, pulmonary function was evaluated

    during standing rest, including forced vital capacity (FVC),

    forced expiratory volume in 1 second (FEV1), maximal voluntary

    ventilation (MVV) and inspiratory airway occlusion pressure (p0.1).

    Results: Increasing mass in the combined load arrangement

    significantly reduced both FVC (control: 6.24 L [±0.16]; 15 kg:

    5.88 [±0.14]; 25 kg: 5.62 [±0.16]; 35 kg: 5.40 [±0.17]; 41 kg: 5.60

    [±0.15]; 54 kg: 5.51 [±0.14]; p < 0.05) and FEV1 (control: 4.86

    L [±0.15]; 15 kg: 4.56 [±0.19]; 25 kg: 4.39 [±0.15]; 35 kg: 4.19

    [±0.11]; 41 kg: 4.3 5[±0.18]; 54 kg: 4.35 [±0.18]; p < 0.05). Inspiratory

    occlusion pressure was augmented while carrying 41 kg and

    54 kg (p < 0.01), but there was no impact of mass on either FEV1/FVC

    (%) or MVV (L/min). When the load was distributed to solely the

    body-armour, there was no additional change to pulmonary function

    for any given mass. In contrast, when the load was distributed

    solely to the backpack, the mass-dependant reductions in FVC and

    FEV1 were reduced for the 35-kg treatment (p < 0.05).

    Conclusions: The loaded backpack and body-amour ensemble

    imposed mass-dependant reductions of up to 13.8% on FVC and up

    to 13.4% on FEV1. Redistributing the mass to either the backpack or

    body-amour caused no further reductions to pulmonary function

    for any given load. Importantly, there was no evidence of airway

    obstruction for any of the treatments. However, inspiratory neuromuscular

    drive was elevated when carrying the very heavy loads

    and this may predispose some individuals to respiratory muscle

    fatigue.

UOW Authors


  •   Hingley, Lachlan (external author)
  •   Caldwell, Joanne N. (external author)
  •   Taylor, Nigel A.S.. (external author)
  •   Peoples, Gregory

Publication Date


  • 2017

Citation


  • Hingley, L., Caldwell, J. N., Taylor, N. A.S.. & Peoples, G. E. (2017). Backpack and body-armour ensembles reduce pulmonary function according to the mass carried and its distribution around the thorax. In International Congress on Soldiers' Physical Performance, 28th November - 1st December, Melbourne, Australia. Journal of Science and Medicine in Sport, 20 S76-S76.

Start Page


  • S76

End Page


  • S76

Volume


  • 20

Place Of Publication


  • Australia