Table 3 The results of the Generalized Additive Mixed Model in modeling heart rate

Parametric coefficients

β

Standard Error

Test statistics

P-value

Intercept

85.214

1.0163

83.850

< 2e-16

Workload

 3.5 kg (Reference category)

 7 Kg

3.492

0.413

8.560

1.73E-15

 10.5 Kg

8.412

0.413

20.376

< 2e-16

Handling states

 1. shorter (Reference category)

 2. same height

1.599

0.478

3.347

0.000932

 3. individual

2.655

0.477

5.568

6.18E-08

 4. taller

4.547

0.493

9.540

< 2e-16

Approximate significance of smooth terms

Edf

Ref.df

F

P-value

S(HR_rest)

3.184

3.586

87.837

< 2e-16

S(body weight)

2.560

2.869

4.675

0.00595

S(height)

3.165

3.328

4.480

0.00393

S(knee height)

2.507

2.700

14.395

5.97E-07

S(shoulder height)

1.000

1.000

44.313

< 2e-16

S(elbow height)

4.419

4.568

45.182

< 2e-16

S(hand height)

4.822

4.900

18.176

< 2e-16