Hi,
I am new to Web components and When ever i am trying to insert a record in Contact Object it was saving with only FirstName,Lastname,MiddleName but i am getting Input in Js but it was not going to ApexClass why?? Can i reason Why??

HTML File:
<template>
    <lightning-card title="Insert Contact" icon-name="standard:contact">
            <div class="slds-p-around_x-small">
                <lightning-input label="FirstName" value={rec.FirstName} onchange={handleFirstNameChange}></lightning-input>
                <lightning-input label="LastName" value={rec.LastName} onchange={handleLastNameChange}></lightning-input>
                <lightning-input type="text" label="Physical" value={rec.Physical} onchange={handlePhysicalChange}></lightning-input><br/>
                <lightning-button label="Save" onclick={handleClick}></lightning-button>
            </div>
        </lightning-card>
</template>

JS File:

import { LightningElement,track} from 'lwc';
// Importing Apex Class method
import createContact from '@salesforce/apex/insertContactApexWeb.saveAccountRecord';
import {ShowToastEvent} from 'lightning/platformShowToastEvent';
import FIRSTNAME_FIELD from '@salesforce/schema/Contact.FirstName__c';
import LASTNAME_FIELD from '@salesforce/schema/Contact.Last_Name__c';
import PHYSICAL_FIELD from '@salesforce/schema/Contact.Physical__c';


export default class InsertAddPersonContact extends LightningElement {
    @track firstname = FIRSTNAME_FIELD;
    @track lastname = LASTNAME_FIELD;
    @track physical = PHYSICAL_FIELD;
    rec = {
        FirstName : this.firstname,
        LastName : this.lastname,
        Physical : this.physical
    }
    handleFirstNameChange(event) {
        this.rec.FirstName = event.target.value;
        window.console.log("FirstName", this.rec.FirstName);
    }
    
    handleLastNameChange(event) {
        this.rec.LastName = event.target.value;
        window.console.log("LastName", this.rec.LastName);
    }
    
    handlePhysicalChange(event) {
        this.rec.PhysicalAttributes = event.target.value;
        window.console.log("Physical", this.rec.Physical);
    }
    handleClick() {
        createContact({ con : this.rec })
            .then(result => {
                this.message = result;
                this.error = undefined;
                if(this.message !== undefined) {
                    this.rec.Name = '';
                    this.rec.Industry = '';
                    this.rec.Phone = '';
                    this.dispatchEvent(
                        new ShowToastEvent({
                            title: 'Success',
                            message: 'Account created',
                            variant: 'success',
                        }),
                    );
                }
                
                window.console.log(JSON.stringify(result));
                window.console.log("result", this.message);
            })
            .catch(error => {
                this.message = undefined;
                this.error = error;
                this.dispatchEvent(
                    new ShowToastEvent({
                        title: 'Error creating record',
                        message: error.body.message,
                        variant: 'error',
                    }),
                );
                window.console.log("error", JSON.stringify(this.error));
            });
    }
    
}

Apex Class
    @AuraEnabled
    public static void saveContactRecord(Contact con){
        System.debug('acc--'+con);
        try{
            insert con;
        }
        catch(Exception ex) {
            throw new AuraHandledException(ex.getMessage());
        }
    }